diff --git a/pkgs/development/libraries/gtkmm/3.x.nix b/pkgs/development/libraries/gtkmm/3.x.nix
index 8b2383f33cce..49055f6b4a95 100644
--- a/pkgs/development/libraries/gtkmm/3.x.nix
+++ b/pkgs/development/libraries/gtkmm/3.x.nix
@@ -12,6 +12,8 @@ stdenv.mkDerivation rec {
     sha256 = "05da4d4b628fb20c8384630ddf478a3b5562952b2d6181fe28d58f6cbc0514f5";
   };
 
+  outputs = [ "out" "dev" ];
+
   nativeBuildInputs = [ pkgconfig ];
   buildInputs = [ epoxy ];