diff --git a/pkgs/development/python-modules/textx/default.nix b/pkgs/development/python-modules/textx/default.nix
index 8b56e0fe739d..0a8ee2236519 100644
--- a/pkgs/development/python-modules/textx/default.nix
+++ b/pkgs/development/python-modules/textx/default.nix
@@ -53,7 +53,7 @@ let
 
     postInstall = ''
       # FileNotFoundError: [Errno 2] No such file or directory: '$out/lib/python3.10/site-packages/textx/textx.tx
-      cp "$src/textx/textx.tx" "$out/lib/${python.libPrefix}/site-packages/${pname}/"
+      cp "$src/textx/textx.tx" "$out/${python.sitePackages}/${pname}/"
 
       # Install tests as the tests output.
       mkdir $testout