diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 3c60ecb3220..16a6544f3ff 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -282,7 +282,7 @@ rec {
       sha256 = "1h62mwy4iz09jqz17nrb9j8y0djd500zdfqwrz9xmdwqzqwixkj2";
     };
 
-    buildInputs = [ clientform ];
+    propagatedBuildInputs = [ clientform ];
 
     meta = {
       description = "Stateful programmatic web browsing in Python";