diff --git a/gtk/gtkcssprovider.c b/gtk/gtkcssprovider.c
index 0a3da2ec12..64dac589dd 100644
--- a/gtk/gtkcssprovider.c
+++ b/gtk/gtkcssprovider.c
@@ -29,6 +29,7 @@
 #include "gtkanimationdescription.h"
 #include "gtk9slice.h"
 #include "gtkcssprovider.h"
+#include "gtkprivate.h"
 
 /**
  * SECTION:gtkcssprovider