diff --git a/pkgs/development/python-modules/marionette-harness/mozlog.nix b/pkgs/development/python-modules/marionette-harness/mozlog.nix
index 7382425f240..5960848ff63 100644
--- a/pkgs/development/python-modules/marionette-harness/mozlog.nix
+++ b/pkgs/development/python-modules/marionette-harness/mozlog.nix
@@ -2,6 +2,7 @@
 , stdenv
 , buildPythonPackage
 , fetchPypi
+, isPy3k
 , blessings
 , mozfile
 }:
@@ -11,12 +12,14 @@ buildPythonPackage rec {
   version = "3.4";
   name = "${pname}-${version}";
 
+  disabled = isPy3k;
+
   src = fetchPypi {
     inherit pname version;
     sha256 = "1m4d9i1kzcmkhipfd5czv05f2s84j1byx3cv4y2irjmwq5v6cyiq";
   };
 
-  propagatedBuildInputs = [ blessings mozfile ]; 
+  propagatedBuildInputs = [ blessings mozfile ];
 
   meta = {
     description = "Mozilla logging library";