diff --git a/tests/test_all.py b/tests/test_all.py
index e5c66b7..fa9c101 100644
--- a/tests/test_all.py
+++ b/tests/test_all.py
@@ -1082,3 +1082,27 @@ def test_issue_97(tmp_path: Path, tiff_image: Path):
     assert result.exit_code == 0
     metas = list(results_dir.glob("run_metadata_*.json"))
     assert len(metas) == 2
+
+
+def test_issue_125(tmp_path: Path):
+    from wsinfer.cli.infer import _get_info_for_save
+    from wsinfer._modellib.models import Weights
+    from wsinfer._modellib.transforms import PatchClassification
+
+    w = Weights(
+        name="foo",
+        architecture="resnet34",
+        # We are testing whether we can still save if file is a Path instance.
+        file=Path(__file__),
+        num_classes=1,
+        transform=PatchClassification(
+            resize_size=299, mean=(0.5, 0.5, 0.5), std=(0.5, 0.5, 0.5)
+        ),
+        patch_size_pixels=350,
+        spacing_um_px=0.25,
+        class_names=["tumor"],
+    )
+
+    info = _get_info_for_save(w)
+    with open(tmp_path / "foo.json", "w") as f:
+        json.dump(info, f)
diff --git a/wsinfer/_modellib/models.py b/wsinfer/_modellib/models.py
index 12bc096..76b4e84 100644
--- a/wsinfer/_modellib/models.py
+++ b/wsinfer/_modellib/models.py
@@ -70,7 +70,7 @@ class Weights:
     class_names: List[str]
     url: Optional[str] = None
     url_file_name: Optional[str] = None
-    file: Optional[str] = None
+    file: Optional[Union[str, Path]] = None
     metadata: Optional[Dict[str, Any]] = None
 
     def __post_init__(self):
diff --git a/wsinfer/cli/infer.py b/wsinfer/cli/infer.py
index 642c1df..0fea2f8 100644
--- a/wsinfer/cli/infer.py
+++ b/wsinfer/cli/infer.py
@@ -154,6 +154,9 @@ def get_stdout(args) -> str:
         weights_file = str(
             Path(torch.hub.get_dir()) / "checkpoints" / weights.url_file_name
         )
+    else:
+        # Weights file could have been a pathlib.Path object.
+        weights_file = str(weights_file)
 
     return {
         "model_weights": {