diff --git a/kitty/data-types.h b/kitty/data-types.h
index 6714e49ac..8c49ac585 100644
--- a/kitty/data-types.h
+++ b/kitty/data-types.h
@@ -24,6 +24,7 @@
 // Required minimum OpenGL version
 #define OPENGL_REQUIRED_VERSION_MAJOR 3
 #ifdef __APPLE__
+#include <xlocale.h>
 #define OPENGL_REQUIRED_VERSION_MINOR 3
 #else
 #define OPENGL_REQUIRED_VERSION_MINOR 1