diff --git a/galaxy/api/views/roles.py b/galaxy/api/views/roles.py
index 460bfbc2e..d0e9db8d5 100644
--- a/galaxy/api/views/roles.py
+++ b/galaxy/api/views/roles.py
@@ -47,7 +47,7 @@ def list(self, request, *args, **kwargs):
             params = {}
             for key, val in request.query_params.items():
                 if key == 'owner__username':
-                    params['namespace__name'] = val
+                    params['namespace__name__iexact'] = val
                 else:
                     params[key] = val
             qs = self.get_queryset()