diff --git a/gdk/Makefile.am b/gdk/Makefile.am
index 9f26228a41..16230cb911 100644
--- a/gdk/Makefile.am
+++ b/gdk/Makefile.am
@@ -119,6 +119,7 @@ gdk_private_headers = 				\
 	gdkframeclockidle.h			\
 	gdkframeclockprivate.h			\
 	gdkglcontextprivate.h			\
+	gdkmonitorprivate.h			\
 	gdkscreenprivate.h			\
 	gdkseatprivate.h			\
 	gdkseatdefaultprivate.h			\