diff --git a/stylix/overlays.nix b/stylix/overlays.nix
index 3285c2f5..0d8f76e3 100644
--- a/stylix/overlays.nix
+++ b/stylix/overlays.nix
@@ -13,7 +13,7 @@
     let
       file = import f;
       attrs =
-        if builtins.typeOf file == "lambda" then
+        if builtins.isFunction file then
           file {
             inherit
               lib