diff --git a/documentation/modules/ROOT/partials/release-notes/release-notes-6.1.0-M2.adoc b/documentation/modules/ROOT/partials/release-notes/release-notes-6.1.0-M2.adoc
index c38852832522..a382adfc6de5 100644
--- a/documentation/modules/ROOT/partials/release-notes/release-notes-6.1.0-M2.adoc
+++ b/documentation/modules/ROOT/partials/release-notes/release-notes-6.1.0-M2.adoc
@@ -38,6 +38,8 @@ repository on GitHub.
   objects.
 * New `selectClasspathResources(String...)` and `selectClasspathResources(List<String)`
   methods in `DiscoverySelectors`.
+* Multiple `junit-platform.properties` files are now supported. Where the same property is set
+  in more than one file, the first value will be used.
 
 
 [[v6.1.0-M2-junit-jupiter]]
diff --git a/junit-platform-launcher/src/main/java/org/junit/platform/launcher/core/LauncherConfigurationParameters.java b/junit-platform-launcher/src/main/java/org/junit/platform/launcher/core/LauncherConfigurationParameters.java
index 001a3a7c440f..f425d7700e98 100644
--- a/junit-platform-launcher/src/main/java/org/junit/platform/launcher/core/LauncherConfigurationParameters.java
+++ b/junit-platform-launcher/src/main/java/org/junit/platform/launcher/core/LauncherConfigurationParameters.java
@@ -255,9 +255,12 @@ private static Properties loadClasspathResource(String configFileName) {
 		Properties props = new Properties();
 
 		try {
-			URL configFileUrl = findConfigFile(configFileName);
-			if (configFileUrl != null) {
-				loadClasspathResource(configFileUrl, props);
+			List<URL> configFileUrls = findConfigFiles(configFileName);
+			// Reverse the list, so that files early on the classpath take priority where there's a conflict
+			Collections.reverse(configFileUrls);
+
+			for (URL url : configFileUrls) {
+				loadClasspathResource(url, props);
 			}
 		}
 		catch (Exception ex) {
@@ -269,15 +272,11 @@ private static Properties loadClasspathResource(String configFileName) {
 		return props;
 	}
 
-	private static @Nullable URL findConfigFile(String configFileName) throws IOException {
+	private static List<URL> findConfigFiles(String configFileName) throws IOException {
 
 		ClassLoader classLoader = ClassLoaderUtils.getDefaultClassLoader();
 		List<URL> urls = Collections.list(classLoader.getResources(configFileName));
 
-		if (urls.size() == 1) {
-			return urls.get(0);
-		}
-
 		if (urls.size() > 1) {
 
 			List<URI> resources = urls.stream() //
@@ -293,14 +292,12 @@ private static Properties loadClasspathResource(String configFileName) {
 						Stream.of(configFileUrl + " (*)"), //
 						resources.stream().skip(1).map(URI::toString) //
 					).collect(joining("\n- ", "\n- ", ""));
-					return "Discovered %d '%s' configuration files on the classpath (see below); only the first (*) will be used.%s".formatted(
+					return "Discovered %d '%s' configuration files on the classpath (see below); properties will be merged, but when there is a conflict, only the first (*) will be used.%s".formatted(
 						resources.size(), configFileName, formattedResourceList);
 				});
 			}
-			return configFileUrl;
 		}
-
-		return null;
+		return urls;
 	}
 
 	private static void loadClasspathResource(URL configFileUrl, Properties props) throws IOException {
diff --git a/platform-tests/src/test/java/org/junit/platform/launcher/core/LauncherConfigurationParametersTests.java b/platform-tests/src/test/java/org/junit/platform/launcher/core/LauncherConfigurationParametersTests.java
index 76548b2c5452..86d3d5151d78 100644
--- a/platform-tests/src/test/java/org/junit/platform/launcher/core/LauncherConfigurationParametersTests.java
+++ b/platform-tests/src/test/java/org/junit/platform/launcher/core/LauncherConfigurationParametersTests.java
@@ -201,11 +201,15 @@ void ignoresSystemPropertyAndConfigFileWhenImplicitLookupsAreDisabled() {
 	}
 
 	@Test
-	void warnsOnMultiplePropertyResources(@TempDir Path tempDir, @TrackLogRecords LogRecordListener logRecordListener)
+	void mergesOnMultiplePropertyResources(@TempDir Path tempDir, @TrackLogRecords LogRecordListener logRecordListener)
 			throws Exception {
+		String uniqueKey = KEY + ".unique-modifier";
+		String someValue = "another value from second config file";
 
 		Properties properties = new Properties();
 		properties.setProperty(KEY, "from second config file");
+
+		properties.setProperty(uniqueKey, someValue);
 		try (var out = Files.newOutputStream(tempDir.resolve(CONFIG_FILE_NAME))) {
 			properties.store(out, "");
 		}
@@ -217,14 +221,18 @@ void warnsOnMultiplePropertyResources(@TempDir Path tempDir, @TrackLogRecords Lo
 			Thread.currentThread().setContextClassLoader(customClassLoader);
 			ConfigurationParameters configParams = fromMapAndFile(Map.of(), CONFIG_FILE_NAME);
 
-			assertThat(configParams.get(KEY)).contains(CONFIG_FILE);
+			assertThat(configParams.get(KEY)).isPresent();
+			assertThat(configParams.get(KEY).orElse("<missing>")).isEqualTo(CONFIG_FILE);
+
+			assertThat(configParams.get(uniqueKey)).isPresent();
+			assertThat(configParams.get(uniqueKey).orElse("<missing>")).isEqualTo(someValue);
 
 			assertThat(logRecordListener.stream(Level.WARNING).map(LogRecord::getMessage)) //
 					.hasSize(1) //
 					.first(as(InstanceOfAssertFactories.STRING)) //
 					.contains("""
 							Discovered 2 '%s' configuration files on the classpath (see below); \
-							only the first (*) will be used.
+							properties will be merged, but when there is a conflict, only the first (*) will be used.
 							- %s (*)
 							- %s"""//
 							.formatted(CONFIG_FILE_NAME, originalResource,