diff --git a/RELEASENOTES.md b/RELEASENOTES.md
index 77e8c95bef..a3d092fe4c 100644
--- a/RELEASENOTES.md
+++ b/RELEASENOTES.md
@@ -42,6 +42,7 @@
     *   Fix a bug that caused multiple ads in an ad pod to be skipped when one
         ad in the ad pod was skipped.
     *   Fix passing an ads response to the `ImaAdsLoader` builder.
+    *   Set the overlay language based on the device locale by default.
 *   Cronet extension:
     *   Fix handling of HTTP status code 200 when making unbounded length range
         requests ([#8090](https://github.com/google/ExoPlayer/issues/8090)).
diff --git a/extensions/ima/src/main/java/com/google/android/exoplayer2/ext/ima/ImaAdsLoader.java b/extensions/ima/src/main/java/com/google/android/exoplayer2/ext/ima/ImaAdsLoader.java
index 65c8920971..1a97861b07 100644
--- a/extensions/ima/src/main/java/com/google/android/exoplayer2/ext/ima/ImaAdsLoader.java
+++ b/extensions/ima/src/main/java/com/google/android/exoplayer2/ext/ima/ImaAdsLoader.java
@@ -82,6 +82,7 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.Locale;
 import java.util.Set;
 import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 
@@ -1912,7 +1913,9 @@ public final class ImaAdsLoader
   private static final class DefaultImaFactory implements ImaUtil.ImaFactory {
     @Override
     public ImaSdkSettings createImaSdkSettings() {
-      return ImaSdkFactory.getInstance().createImaSdkSettings();
+      ImaSdkSettings settings = ImaSdkFactory.getInstance().createImaSdkSettings();
+      settings.setLanguage(getImaLanguageCodeForDefaultLocale());
+      return settings;
     }
 
     @Override
@@ -1953,5 +1956,16 @@ public final class ImaAdsLoader
       return ImaSdkFactory.getInstance()
           .createAdsLoader(context, imaSdkSettings, adDisplayContainer);
     }
+
+    /**
+     * Returns a language code that's suitable for passing to {@link ImaSdkSettings#setLanguage} and
+     * corresponds to the device's {@link Locale#getDefault() default Locale}.
+     */
+    // TODO: It may be possible to define a better mapping onto IMA's supported language codes. See:
+    // https://developers.google.com/interactive-media-ads/docs/sdks/android/client-side/localization.
+    // IMA will fall back to its default language code ("en") if the value returned is unsupported.
+    private static String getImaLanguageCodeForDefaultLocale() {
+      return Util.splitAtFirst(Util.getSystemLanguageCodes()[0], "-")[0];
+    }
   }
 }