diff --git a/onnxruntime/test/python/onnxruntime_test_python.py b/onnxruntime/test/python/onnxruntime_test_python.py
index 3af6e8ccacfb8..f3ebc92409f77 100644
--- a/onnxruntime/test/python/onnxruntime_test_python.py
+++ b/onnxruntime/test/python/onnxruntime_test_python.py
@@ -1307,7 +1307,7 @@ def test_session_options_add_external_initializers(self):
 
     def test_register_custom_ops_library(self):
         if sys.platform.startswith("win"):
-            shared_library = "custom_op_library.dll"
+            shared_library = os.path.abspath("custom_op_library.dll")
             if not os.path.exists(shared_library):
                 raise FileNotFoundError(f"Unable to find '{shared_library}'")
 
@@ -1724,7 +1724,7 @@ def test_register_custom_e_ps_library(self):
             return
 
         if sys.platform.startswith("win"):
-            shared_library = "test_execution_provider.dll"
+            shared_library = os.path.abspath("test_execution_provider.dll")
 
         elif sys.platform.startswith("darwin"):
             # exclude for macos