diff --git a/rten-convert/rten_convert/converter.py b/rten-convert/rten_convert/converter.py
index 2d3bd76e..70beb6d0 100644
--- a/rten-convert/rten_convert/converter.py
+++ b/rten-convert/rten_convert/converter.py
@@ -921,7 +921,7 @@ def op_node_from_onnx_operator(
 
         case "Transpose":
             attrs = sg.TransposeAttrsT()
-            attrs.perm = op_reader.get_attr("perm", "ints", [])
+            attrs.perm = op_reader.get_attr("perm", "ints", None)
 
         case "Trilu":
             attrs = sg.TriluAttrsT()