diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ExecutableMapReduceOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ExecutableMapReduceOperation.java
new file mode 100644
index 000000000..508024e2e
--- /dev/null
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ExecutableMapReduceOperation.java
@@ -0,0 +1,199 @@
+/*
+ * Copyright 2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core;
+
+import java.util.List;
+
+import org.springframework.data.mongodb.core.ExecutableFindOperation.ExecutableFind;
+import org.springframework.data.mongodb.core.mapreduce.MapReduceOptions;
+import org.springframework.data.mongodb.core.query.Query;
+
+/**
+ * {@link ExecutableMapReduceOperation} allows creation and execution of MongoDB mapReduce operations in a fluent API
+ * style. The starting {@literal domainType} is used for mapping an optional {@link Query} provided via {@code matching}
+ * into the MongoDB specific representation. By default, the originating {@literal domainType} is also used for mapping
+ * back the results from the {@link org.bson.Document}. However, it is possible to define an different
+ * {@literal returnType} via {@code as} to mapping the result.<br />
+ * The collection to operate on is by default derived from the initial {@literal domainType} and can be defined there
+ * via {@link org.springframework.data.mongodb.core.mapping.Document}. Using {@code inCollection} allows to override the
+ * collection name for the execution.
+ * 
+ * <pre>
+ *     <code>
+ *         mapReduce(Human.class)
+ *             .map("function() { emit(this.id, this.firstname) }")
+ *             .reduce("function(id, name) { return sum(id, name); }")
+ *             .inCollection("star-wars")
+ *             .as(Jedi.class)
+ *             .matching(query(where("lastname").is("skywalker")))
+ *             .all();
+ *     </code>
+ * </pre>
+ *
+ * @author Christoph Strobl
+ * @since 2.1
+ */
+public interface ExecutableMapReduceOperation {
+
+	/**
+	 * Start creating a mapReduce operation for the given {@literal domainType}.
+	 *
+	 * @param domainType must not be {@literal null}.
+	 * @return new instance of {@link ExecutableFind}.
+	 * @throws IllegalArgumentException if domainType is {@literal null}.
+	 */
+	<T> MapReduceWithMapFunction<T> mapReduce(Class<T> domainType);
+
+	/**
+	 * Trigger mapReduce execution by calling one of the terminating methods.
+	 *
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	interface TerminatingMapReduce<T> {
+
+		/**
+		 * Get the mapReduce results.
+		 *
+		 * @return never {@literal null}.
+		 */
+		List<T> all();
+	}
+
+	/**
+	 * Provide the Javascript {@code function()} used to map matching documents.
+	 *
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	interface MapReduceWithMapFunction<T> {
+
+		/**
+		 * Set the Javascript map {@code function()}.
+		 *
+		 * @param mapFunction must not be {@literal null} nor empty.
+		 * @return new instance of {@link MapReduceWithReduceFunction}.
+		 * @throws IllegalArgumentException if {@literal mapFunction} is {@literal null} or empty.
+		 */
+		MapReduceWithReduceFunction<T> map(String mapFunction);
+
+	}
+
+	/**
+	 * Provide the Javascript {@code function()} used to reduce matching documents.
+	 *
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	interface MapReduceWithReduceFunction<T> {
+
+		/**
+		 * Set the Javascript map {@code function()}.
+		 *
+		 * @param reduceFunction must not be {@literal null} nor empty.
+		 * @return new instance of {@link ExecutableMapReduce}.
+		 * @throws IllegalArgumentException if {@literal reduceFunction} is {@literal null} or empty.
+		 */
+		ExecutableMapReduce<T> reduce(String reduceFunction);
+
+	}
+
+	/**
+	 * Collection override (Optional).
+	 *
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	interface MapReduceWithCollection<T> extends MapReduceWithQuery<T> {
+
+		/**
+		 * Explicitly set the name of the collection to perform the mapReduce operation on. <br />
+		 * Skip this step to use the default collection derived from the domain type.
+		 *
+		 * @param collection must not be {@literal null} nor {@literal empty}.
+		 * @return new instance of {@link MapReduceWithProjection}.
+		 * @throws IllegalArgumentException if collection is {@literal null}.
+		 */
+		MapReduceWithProjection<T> inCollection(String collection);
+	}
+
+	/**
+	 * Input document filter query (Optional).
+	 *
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	interface MapReduceWithQuery<T> extends TerminatingMapReduce<T> {
+
+		/**
+		 * Set the filter query to be used.
+		 *
+		 * @param query must not be {@literal null}.
+		 * @return new instance of {@link TerminatingMapReduce}.
+		 * @throws IllegalArgumentException if query is {@literal null}.
+		 */
+		TerminatingMapReduce<T> matching(Query query);
+	}
+
+	/**
+	 * Result type override (Optional).
+	 *
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	interface MapReduceWithProjection<T> extends MapReduceWithQuery<T> {
+
+		/**
+		 * Define the target type fields should be mapped to. <br />
+		 * Skip this step if you are anyway only interested in the original domain type.
+		 *
+		 * @param resultType must not be {@literal null}.
+		 * @param <R> result type.
+		 * @return new instance of {@link TerminatingMapReduce}.
+		 * @throws IllegalArgumentException if resultType is {@literal null}.
+		 */
+		<R> MapReduceWithQuery<R> as(Class<R> resultType);
+	}
+
+	/**
+	 * Additional mapReduce options (Optional).
+	 *
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	interface MapReduceWithOptions<T> {
+
+		/**
+		 * Set additional options to apply to the mapReduce operation.
+		 *
+		 * @param options must not be {@literal null}.
+		 * @return new instance of {@link ExecutableMapReduce}.
+		 * @throws IllegalArgumentException if options is {@literal null}.
+		 */
+		ExecutableMapReduce<T> with(MapReduceOptions options);
+	}
+
+	/**
+	 * {@link ExecutableMapReduce} provides methods for constructing mapReduce operations in a fluent way.
+	 *
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	interface ExecutableMapReduce<T> extends MapReduceWithMapFunction<T>, MapReduceWithReduceFunction<T>,
+			MapReduceWithCollection<T>, MapReduceWithProjection<T>, MapReduceWithOptions<T> {
+
+	}
+}
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ExecutableMapReduceOperationSupport.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ExecutableMapReduceOperationSupport.java
new file mode 100644
index 000000000..3e7defa53
--- /dev/null
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ExecutableMapReduceOperationSupport.java
@@ -0,0 +1,184 @@
+/*
+ * Copyright 2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core;
+
+import java.util.List;
+
+import org.springframework.data.mongodb.core.mapreduce.MapReduceOptions;
+import org.springframework.data.mongodb.core.query.Query;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+/**
+ * Implementation of {@link ExecutableMapReduceOperation}.
+ *
+ * @author Christoph Strobl
+ * @since 2.1
+ */
+class ExecutableMapReduceOperationSupport implements ExecutableMapReduceOperation {
+
+	private static final Query ALL_QUERY = new Query();
+
+	private final MongoTemplate template;
+
+	/**
+	 * Create new {@link ExecutableMapReduceOperationSupport}.
+	 *
+	 * @param template must not be {@literal null}.
+	 * @throws IllegalArgumentException if template is {@literal null}.
+	 */
+	ExecutableMapReduceOperationSupport(MongoTemplate template) {
+
+		Assert.notNull(template, "Template must not be null!");
+		this.template = template;
+	}
+
+	/*
+	 * (non-Javascript)
+	 * @see in org.springframework.data.mongodb.core.ExecutableMapReduceOperation#mapReduce(java.lang.Class)
+	 */
+	@Override
+	public <T> ExecutableMapReduceSupport<T> mapReduce(Class<T> domainType) {
+
+		Assert.notNull(domainType, "DomainType must not be null!");
+
+		return new ExecutableMapReduceSupport(template, domainType, domainType, null, ALL_QUERY, null, null, null);
+	}
+
+	/**
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	static class ExecutableMapReduceSupport<T>
+			implements ExecutableMapReduce<T>, MapReduceWithOptions<T>, MapReduceWithCollection<T>,
+			MapReduceWithProjection<T>, MapReduceWithQuery<T>, MapReduceWithReduceFunction<T>, MapReduceWithMapFunction<T> {
+
+		private final MongoTemplate template;
+		private final Class<?> domainType;
+		private final Class<T> returnType;
+		private final @Nullable String collection;
+		private final Query query;
+		private final @Nullable String mapFunction;
+		private final @Nullable String reduceFunction;
+		private final @Nullable MapReduceOptions options;
+
+		ExecutableMapReduceSupport(MongoTemplate template, Class<?> domainType, Class<T> returnType, String collection,
+				Query query, @Nullable String mapFunction, @Nullable String reduceFunction, MapReduceOptions options) {
+
+			this.template = template;
+			this.domainType = domainType;
+			this.returnType = returnType;
+			this.collection = collection;
+			this.query = query;
+			this.mapFunction = mapFunction;
+			this.reduceFunction = reduceFunction;
+			this.options = options;
+		}
+
+		/*
+		 * (non-Javascript)
+		 * @see in org.springframework.data.mongodb.core.ExecutableMapReduceOperation.TerminatingMapReduce#all()
+		 */
+		@Override
+		public List<T> all() {
+			return template.mapReduce(query, domainType, getCollectionName(), mapFunction, reduceFunction, options,
+					returnType);
+		}
+
+		/*
+		 * (non-Javascript)
+		 * @see in org.springframework.data.mongodb.core.ExecutableMapReduceOperation.MapReduceWithCollection#inCollection(java.lang.String)
+		 */
+		@Override
+		public MapReduceWithProjection<T> inCollection(String collection) {
+
+			Assert.hasText(collection, "Collection name must not be null nor empty!");
+
+			return new ExecutableMapReduceSupport<>(template, domainType, returnType, collection, query, mapFunction,
+					reduceFunction, options);
+		}
+
+		/*
+		 * (non-Javascript)
+		 * @see in org.springframework.data.mongodb.core.ExecutableMapReduceOperation.MapReduceWithQuery#query(org.springframework.data.mongodb.core.query.Query)
+		 */
+		@Override
+		public TerminatingMapReduce<T> matching(Query query) {
+
+			Assert.notNull(query, "Query must not be null!");
+
+			return new ExecutableMapReduceSupport<>(template, domainType, returnType, collection, query, mapFunction,
+					reduceFunction, options);
+		}
+
+		/*
+		 * (non-Javascript)
+		 * @see in org.springframework.data.mongodb.core.ExecutableMapReduceOperation.MapReduceWithProjection#as(java.lang.Class)
+		 */
+		@Override
+		public <R> MapReduceWithQuery<R> as(Class<R> resultType) {
+
+			Assert.notNull(resultType, "ResultType must not be null!");
+
+			return new ExecutableMapReduceSupport<>(template, domainType, resultType, collection, query, mapFunction,
+					reduceFunction, options);
+		}
+
+		/*
+		 * (non-Javascript)
+		 * @see in org.springframework.data.mongodb.core.ExecutableMapReduceOperation.MapReduceWithOptions#with(org.springframework.data.mongodb.core.mapreduce.MapReduceOptions)
+		 */
+		@Override
+		public ExecutableMapReduce<T> with(MapReduceOptions options) {
+
+			Assert.notNull(options, "Options must not be null! Please consider empty MapReduceOptions#options() instead.");
+
+			return new ExecutableMapReduceSupport<>(template, domainType, returnType, collection, query, mapFunction,
+					reduceFunction, options);
+		}
+
+		/*
+		 * (non-Javascript)
+		 * @see in org.springframework.data.mongodb.core.ExecutableMapReduceOperation.MapReduceWithMapFunction#map(java.lang.String)
+		 */
+		@Override
+		public MapReduceWithReduceFunction<T> map(String mapFunction) {
+
+			Assert.hasText(mapFunction, "MapFunction name must not be null nor empty!");
+
+			return new ExecutableMapReduceSupport<>(template, domainType, returnType, collection, query, mapFunction,
+					reduceFunction, options);
+		}
+
+		/*
+		 * (non-Javascript)
+		 * @see in org.springframework.data.mongodb.core.ExecutableMapReduceOperation.MapReduceWithReduceFunction#reduce(java.lang.String)
+		 */
+		@Override
+		public ExecutableMapReduce<T> reduce(String reduceFunction) {
+
+			Assert.hasText(reduceFunction, "ReduceFunction name must not be null nor empty!");
+
+			return new ExecutableMapReduceSupport<>(template, domainType, returnType, collection, query, mapFunction,
+					reduceFunction, options);
+		}
+
+		private String getCollectionName() {
+			return StringUtils.hasText(collection) ? collection : template.determineCollectionName(domainType);
+		}
+	}
+}
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/FluentMongoOperations.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/FluentMongoOperations.java
index ece0cb776..ff2812020 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/FluentMongoOperations.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/FluentMongoOperations.java
@@ -22,4 +22,4 @@ package org.springframework.data.mongodb.core;
  * @since 2.0
  */
 public interface FluentMongoOperations extends ExecutableFindOperation, ExecutableInsertOperation,
-		ExecutableUpdateOperation, ExecutableRemoveOperation, ExecutableAggregationOperation {}
+		ExecutableUpdateOperation, ExecutableRemoveOperation, ExecutableAggregationOperation, ExecutableMapReduceOperation {}
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java
index 795464704..421ebffa2 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java
@@ -71,7 +71,16 @@ import org.springframework.data.mongodb.core.aggregation.AggregationResults;
 import org.springframework.data.mongodb.core.aggregation.Fields;
 import org.springframework.data.mongodb.core.aggregation.TypeBasedAggregationOperationContext;
 import org.springframework.data.mongodb.core.aggregation.TypedAggregation;
-import org.springframework.data.mongodb.core.convert.*;
+import org.springframework.data.mongodb.core.convert.DbRefResolver;
+import org.springframework.data.mongodb.core.convert.DefaultDbRefResolver;
+import org.springframework.data.mongodb.core.convert.JsonSchemaMapper;
+import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
+import org.springframework.data.mongodb.core.convert.MongoConverter;
+import org.springframework.data.mongodb.core.convert.MongoCustomConversions;
+import org.springframework.data.mongodb.core.convert.MongoJsonSchemaMapper;
+import org.springframework.data.mongodb.core.convert.MongoWriter;
+import org.springframework.data.mongodb.core.convert.QueryMapper;
+import org.springframework.data.mongodb.core.convert.UpdateMapper;
 import org.springframework.data.mongodb.core.index.IndexOperations;
 import org.springframework.data.mongodb.core.index.IndexOperationsProvider;
 import org.springframework.data.mongodb.core.index.MongoMappingEventPublisher;
@@ -132,7 +141,16 @@ import com.mongodb.client.MongoCollection;
 import com.mongodb.client.MongoCursor;
 import com.mongodb.client.MongoDatabase;
 import com.mongodb.client.MongoIterable;
-import com.mongodb.client.model.*;
+import com.mongodb.client.model.CountOptions;
+import com.mongodb.client.model.CreateCollectionOptions;
+import com.mongodb.client.model.DeleteOptions;
+import com.mongodb.client.model.Filters;
+import com.mongodb.client.model.FindOneAndDeleteOptions;
+import com.mongodb.client.model.FindOneAndUpdateOptions;
+import com.mongodb.client.model.ReturnDocument;
+import com.mongodb.client.model.UpdateOptions;
+import com.mongodb.client.model.ValidationAction;
+import com.mongodb.client.model.ValidationLevel;
 import com.mongodb.client.result.DeleteResult;
 import com.mongodb.client.result.UpdateResult;
 import com.mongodb.session.ClientSession;
@@ -1798,9 +1816,29 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 	public <T> MapReduceResults<T> mapReduce(Query query, String inputCollectionName, String mapFunction,
 			String reduceFunction, @Nullable MapReduceOptions mapReduceOptions, Class<T> entityClass) {
 
+		return new MapReduceResults<T>(
+				mapReduce(query, entityClass, inputCollectionName, mapFunction, reduceFunction, mapReduceOptions, entityClass),
+				new Document());
+	}
+
+	/**
+	 * @param query
+	 * @param domainType
+	 * @param inputCollectionName
+	 * @param mapFunction
+	 * @param reduceFunction
+	 * @param mapReduceOptions
+	 * @param resultType
+	 * @param <T>
+	 * @return
+	 * @since 2.1
+	 */
+	public <T> List<T> mapReduce(Query query, Class<?> domainType, String inputCollectionName, String mapFunction,
+			String reduceFunction, @Nullable MapReduceOptions mapReduceOptions, Class<T> resultType) {
+
 		Assert.notNull(query, "Query must not be null!");
 		Assert.notNull(inputCollectionName, "InputCollectionName must not be null!");
-		Assert.notNull(entityClass, "EntityClass must not be null!");
+		Assert.notNull(resultType, "EntityClass must not be null!");
 		Assert.notNull(reduceFunction, "ReduceFunction must not be null!");
 		Assert.notNull(mapFunction, "MapFunction must not be null!");
 
@@ -1818,9 +1856,10 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 			if (query.getMeta() != null && query.getMeta().getMaxTimeMsec() != null) {
 				result = result.maxTime(query.getMeta().getMaxTimeMsec(), TimeUnit.MILLISECONDS);
 			}
-			result = result.sort(getMappedSortObject(query, entityClass));
+			result = result.sort(getMappedSortObject(query, domainType));
 
-			result = result.filter(queryMapper.getMappedObject(query.getQueryObject(), Optional.empty()));
+			result = result
+					.filter(queryMapper.getMappedObject(query.getQueryObject(), mappingContext.getPersistentEntity(domainType)));
 		}
 
 		Optional<Collation> collation = query.getCollation();
@@ -1856,13 +1895,13 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		result = collation.map(Collation::toMongoCollation).map(result::collation).orElse(result);
 
 		List<T> mappedResults = new ArrayList<T>();
-		DocumentCallback<T> callback = new ReadDocumentCallback<T>(mongoConverter, entityClass, inputCollectionName);
+		DocumentCallback<T> callback = new ReadDocumentCallback<T>(mongoConverter, resultType, inputCollectionName);
 
 		for (Document document : result) {
 			mappedResults.add(callback.doWith(document));
 		}
 
-		return new MapReduceResults<T>(mappedResults, new Document());
+		return mappedResults;
 	}
 
 	public <T> GroupByResults<T> group(String inputCollectionName, GroupBy groupBy, Class<T> entityClass) {
@@ -2184,6 +2223,15 @@ public class MongoTemplate implements MongoOperations, ApplicationContextAware,
 		return new ExecutableAggregationOperationSupport(this).aggregateAndReturn(domainType);
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.ExecutableAggregationOperation#aggregateAndReturn(java.lang.Class)
+	 */
+	@Override
+	public <T> ExecutableMapReduce<T> mapReduce(Class<T> domainType) {
+		return new ExecutableMapReduceOperationSupport(this).mapReduce(domainType);
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.core.ExecutableInsertOperation#insert(java.lang.Class)
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveFluentMongoOperations.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveFluentMongoOperations.java
index 85ebb5973..15936c65d 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveFluentMongoOperations.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveFluentMongoOperations.java
@@ -19,7 +19,8 @@ package org.springframework.data.mongodb.core;
  * Stripped down interface providing access to a fluent API that specifies a basic set of reactive MongoDB operations.
  *
  * @author Mark Paluch
+ * @author Christoph Strobl
  * @since 2.0
  */
 public interface ReactiveFluentMongoOperations extends ReactiveFindOperation, ReactiveInsertOperation,
-		ReactiveUpdateOperation, ReactiveRemoveOperation, ReactiveAggregationOperation {}
+		ReactiveUpdateOperation, ReactiveRemoveOperation, ReactiveAggregationOperation, ReactiveMapReduceOperation {}
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMapReduceOperation.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMapReduceOperation.java
new file mode 100644
index 000000000..fca611f74
--- /dev/null
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMapReduceOperation.java
@@ -0,0 +1,199 @@
+/*
+ * Copyright 2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core;
+
+import reactor.core.publisher.Flux;
+
+import org.springframework.data.mongodb.core.ExecutableFindOperation.ExecutableFind;
+import org.springframework.data.mongodb.core.mapreduce.MapReduceOptions;
+import org.springframework.data.mongodb.core.query.Query;
+
+/**
+ * {@link ReactiveMapReduceOperation} allows creation and execution of MongoDB mapReduce operations in a fluent API
+ * style. The starting {@literal domainType} is used for mapping an optional {@link Query} provided via {@code matching}
+ * into the MongoDB specific representation. By default, the originating {@literal domainType} is also used for mapping
+ * back the results from the {@link org.bson.Document}. However, it is possible to define an different
+ * {@literal returnType} via {@code as} to mapping the result.<br />
+ * The collection to operate on is by default derived from the initial {@literal domainType} and can be defined there
+ * via {@link org.springframework.data.mongodb.core.mapping.Document}. Using {@code inCollection} allows to override the
+ * collection name for the execution.
+ * 
+ * <pre>
+ *     <code>
+ *         mapReduce(Human.class)
+ *             .map("function() { emit(this.id, this.firstname) }")
+ *             .reduce("function(id, name) { return sum(id, name); }")
+ *             .inCollection("star-wars")
+ *             .as(Jedi.class)
+ *             .matching(query(where("lastname").is("skywalker")))
+ *             .all();
+ *     </code>
+ * </pre>
+ *
+ * @author Christoph Strobl
+ * @since 2.1
+ */
+public interface ReactiveMapReduceOperation {
+
+	/**
+	 * Start creating a mapReduce operation for the given {@literal domainType}.
+	 *
+	 * @param domainType must not be {@literal null}.
+	 * @return new instance of {@link ExecutableFind}.
+	 * @throws IllegalArgumentException if domainType is {@literal null}.
+	 */
+	<T> MapReduceWithMapFunction<T> mapReduce(Class<T> domainType);
+
+	/**
+	 * Trigger mapReduce execution by calling one of the terminating methods.
+	 *
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	interface TerminatingMapReduce<T> {
+
+		/**
+		 * Get the {@link Flux} emitting mapReduce results.
+		 *
+		 * @return a {@link Flux} emitting the already mapped operation results.
+		 */
+		Flux<T> all();
+	}
+
+	/**
+	 * Provide the Javascript {@code function()} used to map matching documents.
+	 *
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	interface MapReduceWithMapFunction<T> {
+
+		/**
+		 * Set the Javascript map {@code function()}.
+		 *
+		 * @param mapFunction must not be {@literal null} nor empty.
+		 * @return new instance of {@link MapReduceWithReduceFunction}.
+		 * @throws IllegalArgumentException if {@literal mapFunction} is {@literal null} or empty.
+		 */
+		MapReduceWithReduceFunction<T> map(String mapFunction);
+
+	}
+
+	/**
+	 * Provide the Javascript {@code function()} used to reduce matching documents.
+	 *
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	interface MapReduceWithReduceFunction<T> {
+
+		/**
+		 * Set the Javascript map {@code function()}.
+		 *
+		 * @param reduceFunction must not be {@literal null} nor empty.
+		 * @return new instance of {@link ReactiveMapReduce}.
+		 * @throws IllegalArgumentException if {@literal reduceFunction} is {@literal null} or empty.
+		 */
+		ReactiveMapReduce<T> reduce(String reduceFunction);
+
+	}
+
+	/**
+	 * Collection override (Optional).
+	 *
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	interface MapReduceWithCollection<T> extends MapReduceWithQuery<T> {
+
+		/**
+		 * Explicitly set the name of the collection to perform the mapReduce operation on. <br />
+		 * Skip this step to use the default collection derived from the domain type.
+		 *
+		 * @param collection must not be {@literal null} nor {@literal empty}.
+		 * @return new instance of {@link MapReduceWithProjection}.
+		 * @throws IllegalArgumentException if collection is {@literal null}.
+		 */
+		MapReduceWithProjection<T> inCollection(String collection);
+	}
+
+	/**
+	 * Input document filter query (Optional).
+	 *
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	interface MapReduceWithQuery<T> extends TerminatingMapReduce<T> {
+
+		/**
+		 * Set the filter query to be used.
+		 *
+		 * @param query must not be {@literal null}.
+		 * @return new instance of {@link TerminatingMapReduce}.
+		 * @throws IllegalArgumentException if query is {@literal null}.
+		 */
+		TerminatingMapReduce<T> matching(Query query);
+	}
+
+	/**
+	 * Result type override (Optional).
+	 *
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	interface MapReduceWithProjection<T> extends MapReduceWithQuery<T> {
+
+		/**
+		 * Define the target type fields should be mapped to. <br />
+		 * Skip this step if you are anyway only interested in the original domain type.
+		 *
+		 * @param resultType must not be {@literal null}.
+		 * @param <R> result type.
+		 * @return new instance of {@link TerminatingMapReduce}.
+		 * @throws IllegalArgumentException if resultType is {@literal null}.
+		 */
+		<R> MapReduceWithQuery<R> as(Class<R> resultType);
+	}
+
+	/**
+	 * Additional mapReduce options (Optional).
+	 *
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	interface MapReduceWithOptions<T> {
+
+		/**
+		 * Set additional options to apply to the mapReduce operation.
+		 *
+		 * @param options must not be {@literal null}.
+		 * @return new instance of {@link ReactiveMapReduce}.
+		 * @throws IllegalArgumentException if options is {@literal null}.
+		 */
+		ReactiveMapReduce<T> with(MapReduceOptions options);
+	}
+
+	/**
+	 * {@link ReactiveMapReduce} provides methods for constructing reactive mapReduce operations in a fluent way.
+	 *
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	interface ReactiveMapReduce<T> extends MapReduceWithMapFunction<T>, MapReduceWithReduceFunction<T>,
+			MapReduceWithCollection<T>, MapReduceWithProjection<T>, MapReduceWithOptions<T> {
+
+	}
+}
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMapReduceOperationSupport.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMapReduceOperationSupport.java
new file mode 100644
index 000000000..c1a48c4a4
--- /dev/null
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMapReduceOperationSupport.java
@@ -0,0 +1,186 @@
+/*
+ * Copyright 2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core;
+
+import reactor.core.publisher.Flux;
+
+import org.springframework.data.mongodb.core.mapreduce.MapReduceOptions;
+import org.springframework.data.mongodb.core.query.Query;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+/**
+ * Implementation of {@link ReactiveMapReduceOperation}.
+ *
+ * @author Christoph Strobl
+ * @since 2.1
+ */
+class ReactiveMapReduceOperationSupport implements ReactiveMapReduceOperation {
+
+	private static final Query ALL_QUERY = new Query();
+
+	private final ReactiveMongoTemplate template;
+
+	/**
+	 * Create new {@link ReactiveMapReduceOperationSupport}.
+	 *
+	 * @param template must not be {@literal null}.
+	 * @throws IllegalArgumentException if template is {@literal null}.
+	 */
+	ReactiveMapReduceOperationSupport(ReactiveMongoTemplate template) {
+
+		Assert.notNull(template, "Template must not be null!");
+		this.template = template;
+	}
+
+	/*
+	 * (non-Javascript)
+	 * @see in org.springframework.data.mongodb.core.ExecutableMapReduceOperation#mapReduce(java.lang.Class)
+	 */
+	@Override
+	public <T> ReactiveMapReduceSupport<T> mapReduce(Class<T> domainType) {
+
+		Assert.notNull(domainType, "DomainType must not be null!");
+
+		return new ReactiveMapReduceSupport(template, domainType, domainType, null, ALL_QUERY, null, null, null);
+	}
+
+	/**
+	 * @author Christoph Strobl
+	 * @since 2.1
+	 */
+	static class ReactiveMapReduceSupport<T>
+			implements ReactiveMapReduce<T>, MapReduceWithOptions<T>, MapReduceWithCollection<T>, MapReduceWithProjection<T>,
+			MapReduceWithQuery<T>, MapReduceWithReduceFunction<T>, MapReduceWithMapFunction<T> {
+
+		private final ReactiveMongoTemplate template;
+		private final Class<?> domainType;
+		private final Class<T> returnType;
+		private final @Nullable String collection;
+		private final Query query;
+		private final @Nullable String mapFunction;
+		private final @Nullable String reduceFunction;
+		private final @Nullable MapReduceOptions options;
+
+		ReactiveMapReduceSupport(ReactiveMongoTemplate template, Class<?> domainType, Class<T> returnType,
+				String collection, Query query, @Nullable String mapFunction, @Nullable String reduceFunction,
+				MapReduceOptions options) {
+
+			this.template = template;
+			this.domainType = domainType;
+			this.returnType = returnType;
+			this.collection = collection;
+			this.query = query;
+			this.mapFunction = mapFunction;
+			this.reduceFunction = reduceFunction;
+			this.options = options;
+		}
+
+		/*
+		 * (non-Javascript)
+		 * @see in org.springframework.data.mongodb.core.ExecutableMapReduceOperation.TerminatingMapReduce#all()
+		 */
+		@Override
+		public Flux<T> all() {
+
+			return template.mapReduce(query, domainType, getCollectionName(), returnType, mapFunction, reduceFunction,
+					options);
+		}
+
+		/*
+		 * (non-Javascript)
+		 * @see in org.springframework.data.mongodb.core.ReactiveMapReduceOperation.MapReduceWithCollection#inCollection(java.lang.String)
+		 */
+		@Override
+		public MapReduceWithProjection<T> inCollection(String collection) {
+
+			Assert.hasText(collection, "Collection name must not be null nor empty!");
+
+			return new ReactiveMapReduceSupport<>(template, domainType, returnType, collection, query, mapFunction,
+					reduceFunction, options);
+		}
+
+		/*
+		 * (non-Javascript)
+		 * @see in org.springframework.data.mongodb.core.ReactiveMapReduceOperation.MapReduceWithQuery#query(org.springframework.data.mongodb.core.query.Query)
+		 */
+		@Override
+		public TerminatingMapReduce<T> matching(Query query) {
+
+			Assert.notNull(query, "Query must not be null!");
+
+			return new ReactiveMapReduceSupport<>(template, domainType, returnType, collection, query, mapFunction,
+					reduceFunction, options);
+		}
+
+		/*
+		 * (non-Javascript)
+		 * @see in org.springframework.data.mongodb.core.ReactiveMapReduceOperation.MapReduceWithProjection#as(java.lang.Class)
+		 */
+		@Override
+		public <R> MapReduceWithQuery<R> as(Class<R> resultType) {
+
+			Assert.notNull(resultType, "ResultType must not be null!");
+
+			return new ReactiveMapReduceSupport<>(template, domainType, resultType, collection, query, mapFunction,
+					reduceFunction, options);
+		}
+
+		/*
+		 * (non-Javascript)
+		 * @see in org.springframework.data.mongodb.core.ReactiveMapReduceOperation.MapReduceWithOptions#with(org.springframework.data.mongodb.core.mapreduce.MapReduceOptions)
+		 */
+		@Override
+		public ReactiveMapReduce<T> with(MapReduceOptions options) {
+
+			Assert.notNull(options, "Options must not be null! Please consider empty MapReduceOptions#options() instead.");
+
+			return new ReactiveMapReduceSupport<>(template, domainType, returnType, collection, query, mapFunction,
+					reduceFunction, options);
+		}
+
+		/*
+		 * (non-Javascript)
+		 * @see in org.springframework.data.mongodb.core.ReactiveMapReduceOperation.MapReduceWithMapFunction#map(java.lang.String)
+		 */
+		@Override
+		public MapReduceWithReduceFunction<T> map(String mapFunction) {
+
+			Assert.hasText(mapFunction, "MapFunction name must not be null nor empty!");
+
+			return new ReactiveMapReduceSupport<>(template, domainType, returnType, collection, query, mapFunction,
+					reduceFunction, options);
+		}
+
+		/*
+		 * (non-Javascript)
+		 * @see in org.springframework.data.mongodb.core.ReactiveMapReduceOperation.MapReduceWithReduceFunction#reduce(java.lang.String)
+		 */
+		@Override
+		public ReactiveMapReduce<T> reduce(String reduceFunction) {
+
+			Assert.hasText(reduceFunction, "ReduceFunction name must not be null nor empty!");
+
+			return new ReactiveMapReduceSupport<>(template, domainType, returnType, collection, query, mapFunction,
+					reduceFunction, options);
+		}
+
+		private String getCollectionName() {
+			return StringUtils.hasText(collection) ? collection : template.determineCollectionName(domainType);
+		}
+	}
+}
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMongoTemplate.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMongoTemplate.java
index a53ef8168..e2fd433ea 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMongoTemplate.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/ReactiveMongoTemplate.java
@@ -2001,7 +2001,8 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 			if (filterQuery.getLimit() > 0 || (options.getLimit() != null)) {
 
 				if (filterQuery.getLimit() > 0 && (options.getLimit() != null)) {
-					throw new IllegalArgumentException("Both Query and MapReduceOptions define a limit. Please provide the limit only via one of the two.");
+					throw new IllegalArgumentException(
+							"Both Query and MapReduceOptions define a limit. Please provide the limit only via one of the two.");
 				}
 
 				if (filterQuery.getLimit() > 0) {
@@ -2105,6 +2106,15 @@ public class ReactiveMongoTemplate implements ReactiveMongoOperations, Applicati
 		return new ReactiveAggregationOperationSupport(this).aggregateAndReturn(domainType);
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.ReactiveMapReduceOperation#mapReduce(java.lang.Class)
+	 */
+	@Override
+	public <T> ReactiveMapReduce<T> mapReduce(Class<T> domainType) {
+		return new ReactiveMapReduceOperationSupport(this).mapReduce(domainType);
+	}
+
 	/**
 	 * Retrieve and remove all documents matching the given {@code query} by calling {@link #find(Query, Class, String)}
 	 * and {@link #remove(Query, Class, String)}, whereas the {@link Query} for {@link #remove(Query, Class, String)} is
diff --git a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/ExecutableMapReduceOperationSupportUnitTests.java b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/ExecutableMapReduceOperationSupportUnitTests.java
new file mode 100644
index 000000000..a68b72a16
--- /dev/null
+++ b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/ExecutableMapReduceOperationSupportUnitTests.java
@@ -0,0 +1,141 @@
+/*
+ * Copyright 2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.ArgumentMatchers.isNull;
+import static org.mockito.Mockito.*;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mongodb.core.mapping.Field;
+import org.springframework.data.mongodb.core.mapreduce.MapReduceOptions;
+import org.springframework.data.mongodb.core.query.BasicQuery;
+import org.springframework.data.mongodb.core.query.Query;
+
+/**
+ * Unit tests for {@link ExecutableMapReduceOperationSupport}.
+ *
+ * @author Christoph Strobl
+ * @currentRead Beyond the Shadows - Brent Weeks
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class ExecutableMapReduceOperationSupportUnitTests {
+
+	private static final String STAR_WARS = "star-wars";
+	private static final String MAP_FUNCTION = "function() { emit(this.id, this.firstname) }";
+	private static final String REDUCE_FUNCTION = "function(id, name) { return sum(id, name); }";
+
+	@Mock MongoTemplate template;
+
+	ExecutableMapReduceOperationSupport mapReduceOpsSupport;
+
+	@Before
+	public void setUp() {
+
+		when(template.determineCollectionName(eq(Person.class))).thenReturn(STAR_WARS);
+
+		mapReduceOpsSupport = new ExecutableMapReduceOperationSupport(template);
+	}
+
+	@Test(expected = IllegalArgumentException.class) // DATAMONGO-1929
+	public void throwsExceptionOnNullTemplate() {
+		new ExecutableMapReduceOperationSupport(null);
+	}
+
+	@Test(expected = IllegalArgumentException.class) // DATAMONGO-1929
+	public void throwsExceptionOnNullDomainType() {
+		mapReduceOpsSupport.mapReduce(null);
+	}
+
+	@Test // DATAMONGO-1929
+	public void usesExtractedCollectionName() {
+
+		mapReduceOpsSupport.mapReduce(Person.class).map(MAP_FUNCTION).reduce(REDUCE_FUNCTION).all();
+
+		verify(template).mapReduce(any(Query.class), eq(Person.class), eq(STAR_WARS), eq(MAP_FUNCTION), eq(REDUCE_FUNCTION),
+				isNull(), eq(Person.class));
+	}
+
+	@Test // DATAMONGO-1929
+	public void usesExplicitCollectionName() {
+
+		mapReduceOpsSupport.mapReduce(Person.class).map(MAP_FUNCTION).reduce(REDUCE_FUNCTION)
+				.inCollection("the-night-angel").all();
+
+		verify(template).mapReduce(any(Query.class), eq(Person.class), eq("the-night-angel"), eq(MAP_FUNCTION),
+				eq(REDUCE_FUNCTION), isNull(), eq(Person.class));
+	}
+
+	@Test // DATAMONGO-1929
+	public void usesMapReduceOptionsWhenPresent() {
+
+		MapReduceOptions options = MapReduceOptions.options();
+		mapReduceOpsSupport.mapReduce(Person.class).map(MAP_FUNCTION).reduce(REDUCE_FUNCTION).with(options).all();
+
+		verify(template).mapReduce(any(Query.class), eq(Person.class), eq(STAR_WARS), eq(MAP_FUNCTION), eq(REDUCE_FUNCTION),
+				eq(options), eq(Person.class));
+	}
+
+	@Test // DATAMONGO-1929
+	public void usesQueryWhenPresent() {
+
+		Query query = new BasicQuery("{ 'lastname' : 'skywalker' }");
+		mapReduceOpsSupport.mapReduce(Person.class).map(MAP_FUNCTION).reduce(REDUCE_FUNCTION).matching(query).all();
+
+		verify(template).mapReduce(eq(query), eq(Person.class), eq(STAR_WARS), eq(MAP_FUNCTION), eq(REDUCE_FUNCTION),
+				isNull(), eq(Person.class));
+	}
+
+	@Test // DATAMONGO-1929
+	public void usesProjectionWhenPresent() {
+
+		mapReduceOpsSupport.mapReduce(Person.class).map(MAP_FUNCTION).reduce(REDUCE_FUNCTION).as(Jedi.class).all();
+
+		verify(template).mapReduce(any(Query.class), eq(Person.class), eq(STAR_WARS), eq(MAP_FUNCTION), eq(REDUCE_FUNCTION),
+				isNull(), eq(Jedi.class));
+	}
+
+	interface Contact {}
+
+	@Data
+	@org.springframework.data.mongodb.core.mapping.Document(collection = STAR_WARS)
+	static class Person implements Contact {
+
+		@Id String id;
+		String firstname;
+		String lastname;
+		Object ability;
+		Person father;
+	}
+
+	@Data
+	@AllArgsConstructor
+	@NoArgsConstructor
+	static class Jedi {
+
+		@Field("firstname") String name;
+	}
+}
diff --git a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/ReactiveMapReduceOperationSupportUnitTests.java b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/ReactiveMapReduceOperationSupportUnitTests.java
new file mode 100644
index 000000000..3f3209721
--- /dev/null
+++ b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/ReactiveMapReduceOperationSupportUnitTests.java
@@ -0,0 +1,141 @@
+/*
+ * Copyright 2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.ArgumentMatchers.isNull;
+import static org.mockito.Mockito.*;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mongodb.core.mapping.Field;
+import org.springframework.data.mongodb.core.mapreduce.MapReduceOptions;
+import org.springframework.data.mongodb.core.query.BasicQuery;
+import org.springframework.data.mongodb.core.query.Query;
+
+/**
+ * Unit tests for {@link ReactiveMapReduceOperationSupport}.
+ *
+ * @author Christoph Strobl
+ * @currentRead Beyond the Shadows - Brent Weeks
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class ReactiveMapReduceOperationSupportUnitTests {
+
+	private static final String STAR_WARS = "star-wars";
+	private static final String MAP_FUNCTION = "function() { emit(this.id, this.firstname) }";
+	private static final String REDUCE_FUNCTION = "function(id, name) { return sum(id, name); }";
+
+	@Mock ReactiveMongoTemplate template;
+
+	ReactiveMapReduceOperationSupport mapReduceOpsSupport;
+
+	@Before
+	public void setUp() {
+
+		when(template.determineCollectionName(eq(Person.class))).thenReturn(STAR_WARS);
+
+		mapReduceOpsSupport = new ReactiveMapReduceOperationSupport(template);
+	}
+
+	@Test(expected = IllegalArgumentException.class) // DATAMONGO-1929
+	public void throwsExceptionOnNullTemplate() {
+		new ExecutableMapReduceOperationSupport(null);
+	}
+
+	@Test(expected = IllegalArgumentException.class) // DATAMONGO-1929
+	public void throwsExceptionOnNullDomainType() {
+		mapReduceOpsSupport.mapReduce(null);
+	}
+
+	@Test // DATAMONGO-1929
+	public void usesExtractedCollectionName() {
+
+		mapReduceOpsSupport.mapReduce(Person.class).map(MAP_FUNCTION).reduce(REDUCE_FUNCTION).all();
+
+		verify(template).mapReduce(any(Query.class), eq(Person.class), eq(STAR_WARS), eq(Person.class), eq(MAP_FUNCTION),
+				eq(REDUCE_FUNCTION), isNull());
+	}
+
+	@Test // DATAMONGO-1929
+	public void usesExplicitCollectionName() {
+
+		mapReduceOpsSupport.mapReduce(Person.class).map(MAP_FUNCTION).reduce(REDUCE_FUNCTION)
+				.inCollection("the-night-angel").all();
+
+		verify(template).mapReduce(any(Query.class), eq(Person.class), eq("the-night-angel"), eq(Person.class),
+				eq(MAP_FUNCTION), eq(REDUCE_FUNCTION), isNull());
+	}
+
+	@Test // DATAMONGO-1929
+	public void usesMapReduceOptionsWhenPresent() {
+
+		MapReduceOptions options = MapReduceOptions.options();
+		mapReduceOpsSupport.mapReduce(Person.class).map(MAP_FUNCTION).reduce(REDUCE_FUNCTION).with(options).all();
+
+		verify(template).mapReduce(any(Query.class), eq(Person.class), eq(STAR_WARS), eq(Person.class), eq(MAP_FUNCTION),
+				eq(REDUCE_FUNCTION), eq(options));
+	}
+
+	@Test // DATAMONGO-1929
+	public void usesQueryWhenPresent() {
+
+		Query query = new BasicQuery("{ 'lastname' : 'skywalker' }");
+		mapReduceOpsSupport.mapReduce(Person.class).map(MAP_FUNCTION).reduce(REDUCE_FUNCTION).matching(query).all();
+
+		verify(template).mapReduce(eq(query), eq(Person.class), eq(STAR_WARS), eq(Person.class), eq(MAP_FUNCTION),
+				eq(REDUCE_FUNCTION), isNull());
+	}
+
+	@Test // DATAMONGO-1929
+	public void usesProjectionWhenPresent() {
+
+		mapReduceOpsSupport.mapReduce(Person.class).map(MAP_FUNCTION).reduce(REDUCE_FUNCTION).as(Jedi.class).all();
+
+		verify(template).mapReduce(any(Query.class), eq(Person.class), eq(STAR_WARS), eq(Jedi.class), eq(MAP_FUNCTION),
+				eq(REDUCE_FUNCTION), isNull());
+	}
+
+	interface Contact {}
+
+	@Data
+	@org.springframework.data.mongodb.core.mapping.Document(collection = STAR_WARS)
+	static class Person implements Contact {
+
+		@Id String id;
+		String firstname;
+		String lastname;
+		Object ability;
+		Person father;
+	}
+
+	@Data
+	@AllArgsConstructor
+	@NoArgsConstructor
+	static class Jedi {
+
+		@Field("firstname") String name;
+	}
+}