diff --git a/src/diffusers/pipelines/onnx_utils.py b/src/diffusers/pipelines/onnx_utils.py
index 43827c7a61f2..37c27b7d4b1e 100644
--- a/src/diffusers/pipelines/onnx_utils.py
+++ b/src/diffusers/pipelines/onnx_utils.py
@@ -172,7 +172,7 @@ def _from_pretrained(
         # load model from local directory
         if os.path.isdir(model_id):
             model = OnnxRuntimeModel.load_model(
-                os.path.join(model_id, model_file_name), provider=provider, sess_options=sess_options
+                Path(model_id, model_file_name).as_posix(), provider=provider, sess_options=sess_options
             )
             kwargs["model_save_dir"] = Path(model_id)
         # load model from hub