diff --git a/gdk/mir/gdkmir.h b/gdk/mir/gdkmir.h
index 1ab0a2867a..a1c15d1a12 100644
--- a/gdk/mir/gdkmir.h
+++ b/gdk/mir/gdkmir.h
@@ -25,7 +25,7 @@
 #define GDK_IS_MIR_DISPLAY(object)        (G_TYPE_CHECK_INSTANCE_TYPE ((object), GDK_TYPE_MIR_DISPLAY))
 
 #define GDK_TYPE_MIR_WINDOW              (gdk_mir_window_get_type ())
-#define GDK_IS_WINDOW_MIR(object)        (G_TYPE_CHECK_INSTANCE_TYPE ((object), GDK_TYPE_WINDOW_MIR))
+#define GDK_IS_WINDOW_MIR(object)        (G_TYPE_CHECK_INSTANCE_TYPE ((object), GDK_TYPE_MIR_WINDOW))
 
 GDK_AVAILABLE_IN_3_10
 GType gdk_mir_display_get_type (void);