diff --git a/pkgs/by-name/tu/turses/package.nix b/pkgs/by-name/tu/turses/package.nix
index 93e689feb27c..a24ee8d7dcb5 100644
--- a/pkgs/by-name/tu/turses/package.nix
+++ b/pkgs/by-name/tu/turses/package.nix
@@ -71,7 +71,7 @@ buildPythonPackage rec {
     tox
   ];
 
-  LC_ALL = "en_US.UTF-8";
+  env.LC_ALL = "en_US.UTF-8";
 
   patches = [
     (fetchpatch {