diff --git a/src/lib/platform/OSXKeyState.h b/src/lib/platform/OSXKeyState.h
index b0c69662d..ff094df8b 100644
--- a/src/lib/platform/OSXKeyState.h
+++ b/src/lib/platform/OSXKeyState.h
@@ -13,7 +13,6 @@
 #include <Carbon/Carbon.h>
 
 #include <map>
-#include <set>
 #include <vector>
 
 class IOSXKeyResource;