diff --git a/dom/gamepad/cocoa/CocoaGamepad.cpp b/dom/gamepad/cocoa/CocoaGamepad.cpp
index 24786f5ef6..7fcf48532b 100644
--- a/dom/gamepad/cocoa/CocoaGamepad.cpp
+++ b/dom/gamepad/cocoa/CocoaGamepad.cpp
@@ -10,6 +10,7 @@
 #include "mozilla/dom/Gamepad.h"
 #include "mozilla/dom/GamepadPlatformService.h"
 #include "mozilla/ArrayUtils.h"
+#include "mozilla/Unused.h"
 #include "nsThreadUtils.h"
 #include <CoreFoundation/CoreFoundation.h>
 #include <IOKit/hid/IOHIDBase.h>