diff --git a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/PrefsHelper.java b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/PrefsHelper.java
index 85b4f9b96e2c..08994d5af446 100644
--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/PrefsHelper.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/PrefsHelper.java
@@ -33,6 +33,7 @@ public final class PrefsHelper {
         INT_TO_STRING_PREFS.add("network.cookie.cookieBehavior");
         INT_TO_STRING_PREFS.add("home.sync.updateMode");
         INT_TO_STRING_PREFS.add("browser.image_blocking");
+        INT_TO_STRING_PREFS.add("media.autoplay.default");
         INT_TO_BOOL_PREFS.add("browser.display.use_document_fonts");
     }