diff --git a/pkgs/development/python-modules/twisted/default.nix b/pkgs/development/python-modules/twisted/default.nix
index 758b3f4eea0b8..bcd2f6d5e06bb 100644
--- a/pkgs/development/python-modules/twisted/default.nix
+++ b/pkgs/development/python-modules/twisted/default.nix
@@ -142,7 +142,7 @@ buildPythonPackage rec {
   # Generate Twisted's plug-in cache. Twisted users must do it as well. See
   # http://twistedmatrix.com/documents/current/core/howto/plugin.html#auto3
   # and http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=477103 for details.
-  postFixup = ''
+  postFixup = lib.optionalString (stdenv.buildPlatform.canExecute stdenv.hostPlatform) ''
     $out/bin/twistd --help > /dev/null
   '';