diff --git a/backends/xnnpack/test/tester/tester.py b/backends/xnnpack/test/tester/tester.py
index 1b6f03512bd..d6e2f12884a 100644
--- a/backends/xnnpack/test/tester/tester.py
+++ b/backends/xnnpack/test/tester/tester.py
@@ -1,4 +1,5 @@
 # Copyright (c) Meta Platforms, Inc. and affiliates.
+# Copyright 2025 Arm Limited and/or its affiliates.
 # All rights reserved.
 #
 # This source code is licensed under the BSD-style license found in the
@@ -679,6 +680,9 @@ def _assert_outputs_equal(model_output, ref_output, atol=1e-03, rtol=1e-03):
         for i in range(len(model_output)):
             model = model_output[i]
             ref = ref_output[i]
+            assert (
+                ref.shape == model.shape
+            ), f"Output {i} shape {model.shape} does not match reference output shape {ref.shape}"
             assert torch.allclose(
                 model,
                 ref,