diff --git a/pkgs/development/interpreters/python/build-python-package-setuptools.nix b/pkgs/development/interpreters/python/build-python-package-setuptools.nix
index f077533ecfe4..c6e21ff4fede 100644
--- a/pkgs/development/interpreters/python/build-python-package-setuptools.nix
+++ b/pkgs/development/interpreters/python/build-python-package-setuptools.nix
@@ -49,7 +49,7 @@ in attrs // {
       export PATH="$tmp_path/bin:$PATH"
       export PYTHONPATH="$tmp_path/${python.sitePackages}:$PYTHONPATH"
       mkdir -p $tmp_path/${python.sitePackages}
-      ${bootstrapped-pip}/bin/pip install -e . --prefix $tmp_path
+      ${bootstrapped-pip}/bin/pip install -e . --prefix $tmp_path >&2
     fi
     ${postShellHook}
   '';