diff --git a/spring-test/src/main/java/org/springframework/test/context/bean/override/BeanOverrideHandler.java b/spring-test/src/main/java/org/springframework/test/context/bean/override/BeanOverrideHandler.java
index db89dd6e185..06eeaaf1fa9 100644
--- a/spring-test/src/main/java/org/springframework/test/context/bean/override/BeanOverrideHandler.java
+++ b/spring-test/src/main/java/org/springframework/test/context/bean/override/BeanOverrideHandler.java
@@ -132,7 +132,7 @@ public abstract class BeanOverrideHandler {
 
 	private static List<BeanOverrideHandler> findHandlers(Class<?> testClass, boolean localFieldsOnly) {
 		List<BeanOverrideHandler> handlers = new ArrayList<>();
-		findHandlers(testClass, testClass, handlers, localFieldsOnly);
+		findHandlers(testClass, testClass, handlers, localFieldsOnly, new HashSet<>());
 		return handlers;
 	}
 
@@ -146,26 +146,30 @@ public abstract class BeanOverrideHandler {
 	 * @param testClass the original test class
 	 * @param handlers the list of handlers found
 	 * @param localFieldsOnly whether to search only on local fields within the type hierarchy
+	 * @param visitedEnclosingClasses the set of enclosing classes already visited
 	 * @since 6.2.2
 	 */
 	private static void findHandlers(Class<?> clazz, Class<?> testClass, List<BeanOverrideHandler> handlers,
-			boolean localFieldsOnly) {
+			boolean localFieldsOnly, Set<Class<?>> visitedEnclosingClasses) {
 
 		// 1) Search enclosing class hierarchy.
 		if (!localFieldsOnly && TestContextAnnotationUtils.searchEnclosingClass(clazz)) {
-			findHandlers(clazz.getEnclosingClass(), testClass, handlers, localFieldsOnly);
+			Class<?> enclosingClass = clazz.getEnclosingClass();
+			if (visitedEnclosingClasses.add(enclosingClass)) {
+				findHandlers(enclosingClass, testClass, handlers, localFieldsOnly, visitedEnclosingClasses);
+			}
 		}
 
 		// 2) Search class hierarchy.
 		Class<?> superclass = clazz.getSuperclass();
 		if (superclass != null && superclass != Object.class) {
-			findHandlers(superclass, testClass, handlers, localFieldsOnly);
+			findHandlers(superclass, testClass, handlers, localFieldsOnly, visitedEnclosingClasses);
 		}
 
 		if (!localFieldsOnly) {
 			// 3) Search interfaces.
 			for (Class<?> ifc : clazz.getInterfaces()) {
-				findHandlers(ifc, testClass, handlers, localFieldsOnly);
+				findHandlers(ifc, testClass, handlers, localFieldsOnly, visitedEnclosingClasses);
 			}
 
 			// 4) Process current class.
diff --git a/spring-test/src/test/java/org/springframework/test/context/bean/override/mockito/MockitoBeanNestedAndTypeHierarchiesTests.java b/spring-test/src/test/java/org/springframework/test/context/bean/override/mockito/MockitoBeanNestedAndTypeHierarchiesTests.java
new file mode 100644
index 00000000000..72babe68674
--- /dev/null
+++ b/spring-test/src/test/java/org/springframework/test/context/bean/override/mockito/MockitoBeanNestedAndTypeHierarchiesTests.java
@@ -0,0 +1,76 @@
+/*
+ * Copyright 2002-2025 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
+ *
+ *      https://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.test.context.bean.override.mockito;
+
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.ApplicationContext;
+import org.springframework.test.context.bean.override.example.ExampleService;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.test.mockito.MockitoAssertions.assertIsMock;
+
+/**
+ * Integration tests for {@link MockitoBean @MockitoBean} which verify that
+ * {@code @MockitoBean} fields are not discovered more than once when searching
+ * intertwined enclosing class hierarchies and type hierarchies.
+ *
+ * @author Sam Brannen
+ * @since 6.2.3
+ * @see <a href="https://github.com/spring-projects/spring-framework/issues/34324">gh-34324</a>
+ */
+@ExtendWith(SpringExtension.class)
+class MockitoBeanNestedAndTypeHierarchiesTests {
+
+	@Autowired
+	ApplicationContext enclosingContext;
+
+	@MockitoBean
+	ExampleService service;
+
+
+	@Test
+	void topLevelTest() {
+		assertIsMock(service);
+
+		// The following are prerequisites for the reported regression.
+		assertThat(NestedTests.class.getSuperclass())
+				.isEqualTo(AbstractBaseClassForNestedTests.class);
+		assertThat(NestedTests.class.getEnclosingClass())
+				.isEqualTo(AbstractBaseClassForNestedTests.class.getEnclosingClass())
+				.isEqualTo(getClass());
+	}
+
+
+	abstract class AbstractBaseClassForNestedTests {
+
+		@Test
+		void nestedTest(ApplicationContext nestedContext) {
+			assertIsMock(service);
+			assertThat(enclosingContext).isSameAs(nestedContext);
+		}
+	}
+
+	@Nested
+	class NestedTests extends AbstractBaseClassForNestedTests {
+	}
+
+}
diff --git a/spring-test/src/test/java/org/springframework/test/context/bean/override/mockito/mockbeans/MockitoBeansByTypeIntegrationTests.java b/spring-test/src/test/java/org/springframework/test/context/bean/override/mockito/mockbeans/MockitoBeansByTypeIntegrationTests.java
index c70fc89f612..e58b2e888ce 100644
--- a/spring-test/src/test/java/org/springframework/test/context/bean/override/mockito/mockbeans/MockitoBeansByTypeIntegrationTests.java
+++ b/spring-test/src/test/java/org/springframework/test/context/bean/override/mockito/mockbeans/MockitoBeansByTypeIntegrationTests.java
@@ -90,7 +90,7 @@ class MockitoBeansByTypeIntegrationTests implements TestInterface01 {
 
 
 	@MockitoBean(types = Service09.class)
-	static class BaseTestCase implements TestInterface08 {
+	class BaseTestCase implements TestInterface08 {
 
 		@Autowired
 		Service08 service08;