diff --git a/pkgs/development/python-modules/avro3k/default.nix b/pkgs/development/python-modules/avro3k/default.nix
index 6f7474e6f40e..94c4d665a032 100644
--- a/pkgs/development/python-modules/avro3k/default.nix
+++ b/pkgs/development/python-modules/avro3k/default.nix
@@ -31,5 +31,6 @@ buildPythonPackage rec {
     description = "Serialization and RPC framework";
     mainProgram = "avro";
     homepage = "https://pypi.python.org/pypi/avro3k/";
+    license = lib.licenses.asl20;
   };
 }