diff --git a/robolectric/src/test/java/org/robolectric/shadows/ShadowLocaleManagerTest.java b/robolectric/src/test/java/org/robolectric/shadows/ShadowLocaleManagerTest.java
index aa7cc4c4721..e53b3dd53b5 100644
--- a/robolectric/src/test/java/org/robolectric/shadows/ShadowLocaleManagerTest.java
+++ b/robolectric/src/test/java/org/robolectric/shadows/ShadowLocaleManagerTest.java
@@ -45,6 +45,18 @@ public void setApplicationLocales_updatesMap() {
         .isEqualTo(DEFAULT_LOCALES);
   }
 
+  @Test
+  public void setApplicationLocales_defaultPackage_updatesMap() {
+    // empty map before set is called.
+    assertThat(localeManager.getApplicationLocales(DEFAULT_PACKAGE_NAME))
+        .isEqualTo(LocaleList.getEmptyLocaleList());
+
+    localeManager.setApplicationLocales(DEFAULT_LOCALES);
+
+    shadowLocaleManager.enforceInstallerCheck(false);
+    assertThat(localeManager.getApplicationLocales()).isEqualTo(DEFAULT_LOCALES);
+  }
+
   @Test
   public void getApplicationLocales_fetchAsInstaller_returnsLocales() {
     localeManager.setApplicationLocales(DEFAULT_PACKAGE_NAME, DEFAULT_LOCALES);
diff --git a/shadows/framework/src/main/java/org/robolectric/shadows/ShadowLocaleManager.java b/shadows/framework/src/main/java/org/robolectric/shadows/ShadowLocaleManager.java
index 2244a2be736..d96a1e2c441 100644
--- a/shadows/framework/src/main/java/org/robolectric/shadows/ShadowLocaleManager.java
+++ b/shadows/framework/src/main/java/org/robolectric/shadows/ShadowLocaleManager.java
@@ -12,6 +12,7 @@
 import java.util.Set;
 import org.robolectric.annotation.Implementation;
 import org.robolectric.annotation.Implements;
+import org.robolectric.versioning.AndroidVersions.U;
 
 /** Shadow of {@link LocaleManager} */
 @Implements(value = LocaleManager.class, minSdk = VERSION_CODES.TIRAMISU, isInAndroidSdk = false)
@@ -48,13 +49,26 @@ protected LocaleList getApplicationLocales(String packageName) {
   /**
    * Stores the passed locales for the given package in-memory.
    *
+   * <p>Starting in Android U, this method just invokes the 3-arg version (below).
+   *
    * <p>Use this method in tests to substitute call for {@link LocaleManager#setApplicationLocales}.
    */
-  @Implementation
+  @Implementation(maxSdk = VERSION_CODES.TIRAMISU)
   protected void setApplicationLocales(String packageName, LocaleList locales) {
     appLocales.put(packageName, locales);
   }
 
+  /**
+   * Stores the passed locales for the given package in-memory.
+   *
+   * <p>Use this method in tests to substitute call for {@link LocaleManager#setApplicationLocales}.
+   */
+  @Implementation(minSdk = U.SDK_INT)
+  protected void setApplicationLocales(
+      String packageName, LocaleList locales, boolean fromDelegate) {
+    setApplicationLocales(packageName, locales);
+  }
+
   @RequiresApi(api = VERSION_CODES.N)
   @Implementation
   protected LocaleList getSystemLocales() {