diff --git a/pkgs/development/python-modules/seekpath/default.nix b/pkgs/development/python-modules/seekpath/default.nix
index b2909dea51df..0c06dd06c405 100644
--- a/pkgs/development/python-modules/seekpath/default.nix
+++ b/pkgs/development/python-modules/seekpath/default.nix
@@ -22,7 +22,7 @@ buildPythonPackage rec {
     hash = "sha256-mrutQCSSiiLPt0KEohZeYcQ8aw2Jhy02bEvn6Of8w6U=";
   };
 
-  LC_ALL = "en_US.utf-8";
+  env.LC_ALL = "en_US.utf-8";
 
   build-system = [ setuptools ];