diff --git a/basis/ui/backend/gtk/gtk.factor b/basis/ui/backend/gtk/gtk.factor
index 3d8b330a4b..9afba9e21e 100644
--- a/basis/ui/backend/gtk/gtk.factor
+++ b/basis/ui/backend/gtk/gtk.factor
@@ -529,8 +529,9 @@ M: gtk-ui-backend (with-ui)
         ] with-destructors
     ] ui-running ;
 
-
-gtk-ui-backend ui-backend set-global
+os unix? os macosx? not and [
+    gtk-ui-backend ui-backend set-global
+] when
 
 { "ui.backend.gtk" "io.backend.unix" }
 "ui.backend.gtk.io.unix" require-when