diff --git a/pkgs/development/python-modules/hy/default.nix b/pkgs/development/python-modules/hy/default.nix
index 5e994c93ca33..6dc9c316e09c 100644
--- a/pkgs/development/python-modules/hy/default.nix
+++ b/pkgs/development/python-modules/hy/default.nix
@@ -25,7 +25,7 @@ buildPythonPackage rec {
   };
 
   # https://github.com/hylang/hy/blob/1.0a4/get_version.py#L9-L10
-  HY_VERSION = version;
+  env.HY_VERSION = version;
 
   build-system = [ setuptools ];