diff --git a/spring-modulith-core/src/main/java/org/springframework/modulith/core/ApplicationModule.java b/spring-modulith-core/src/main/java/org/springframework/modulith/core/ApplicationModule.java
index df544d3c..0f0f7d5b 100644
--- a/spring-modulith-core/src/main/java/org/springframework/modulith/core/ApplicationModule.java
+++ b/spring-modulith-core/src/main/java/org/springframework/modulith/core/ApplicationModule.java
@@ -414,6 +414,24 @@ public class ApplicationModule {
 		return getType(candidate).isPresent();
 	}
 
+	/**
+	 * Returns whether the {@link ApplicationModule} contains the package with the given name, which means the given
+	 * package is either the module's base package or a sub package of it.
+	 * 
+	 * @param packageName must not be {@literal null} or empty.
+	 * @return whether the {@link ApplicationModule} contains the package with the given name.
+	 * @since 1.0.2
+	 */
+	boolean containsPackage(String packageName) {
+
+		Assert.hasText(packageName, "Package name must not be null or empty!");
+
+		var basePackageName = basePackage.getName();
+
+		return packageName.equals(basePackageName)
+				|| packageName.startsWith(basePackageName + ".");
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see java.lang.Object#equals(java.lang.Object)
diff --git a/spring-modulith-core/src/main/java/org/springframework/modulith/core/ApplicationModules.java b/spring-modulith-core/src/main/java/org/springframework/modulith/core/ApplicationModules.java
index 6fe2e8b6..3310d107 100644
--- a/spring-modulith-core/src/main/java/org/springframework/modulith/core/ApplicationModules.java
+++ b/spring-modulith-core/src/main/java/org/springframework/modulith/core/ApplicationModules.java
@@ -326,10 +326,16 @@ public class ApplicationModules implements Iterable<ApplicationModule> {
 		return getModuleByType(candidate.getName());
 	}
 
+	/**
+	 * Returns the {@link ApplicationModule} containing the given package.
+	 * 
+	 * @param name must not be {@literal null} or empty.
+	 * @return will never be {@literal null}.
+	 */
 	public Optional<ApplicationModule> getModuleForPackage(String name) {
 
 		return modules.values().stream() //
-				.filter(it -> name.startsWith(it.getBasePackage().getName())) //
+				.filter(it -> it.containsPackage(name)) //
 				.findFirst();
 	}
 
diff --git a/spring-modulith-core/src/test/java/org/springframework/modulith/core/ModuleUnitTest.java b/spring-modulith-core/src/test/java/org/springframework/modulith/core/ModuleUnitTest.java
index f1ec17a1..40c6fc76 100644
--- a/spring-modulith-core/src/test/java/org/springframework/modulith/core/ModuleUnitTest.java
+++ b/spring-modulith-core/src/test/java/org/springframework/modulith/core/ModuleUnitTest.java
@@ -16,11 +16,13 @@
 package org.springframework.modulith.core;
 
 import static org.assertj.core.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.*;
 
 import java.util.List;
 
 import javax.sql.DataSource;
 
+import org.junit.jupiter.api.DynamicTest;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.TestInstance;
 import org.junit.jupiter.api.TestInstance.Lifecycle;
@@ -83,4 +85,13 @@ class ModuleUnitTest {
 				.<Class<?>> extracting(JavaClass::reflect)
 				.containsExactly(SampleAggregate.class);
 	}
+	
+	@Test // GH-319
+	void containsPackage() {	
+		
+		assertThat(module.containsPackage(packageName)).isTrue();
+		assertThat(module.containsPackage(packageName + ".foo")).isTrue();
+		
+		assertThat(module.containsPackage(packageName + "foo")).isFalse();
+	}
 }