diff --git a/roboflow/cli/handlers/_aliases.py b/roboflow/cli/handlers/_aliases.py
index 70895d39..301c2dab 100644
--- a/roboflow/cli/handlers/_aliases.py
+++ b/roboflow/cli/handlers/_aliases.py
@@ -63,7 +63,10 @@ def upload_alias(
         project: Annotated[str, typer.Option("-p", "--project", help="Project ID")],
         annotation: Annotated[Optional[str], typer.Option("-a", "--annotation", help="Annotation file")] = None,
         labelmap: Annotated[Optional[str], typer.Option("-m", "--labelmap", help="Labelmap file")] = None,
-        split: Annotated[str, typer.Option("-s", "--split", help="Split (train/valid/test)")] = "train",
+        split: Annotated[
+            Optional[str],
+            typer.Option("-s", "--split", help="Override split for all uploaded images (default: infer from folder)"),
+        ] = None,
         num_retries: Annotated[int, typer.Option("-r", "--retries", help="Retry count")] = 0,
         batch: Annotated[Optional[str], typer.Option("-b", "--batch", help="Batch name")] = None,
         tag_names: Annotated[Optional[str], typer.Option("-t", "--tag", help="Tag names")] = None,
diff --git a/roboflow/cli/handlers/image.py b/roboflow/cli/handlers/image.py
index a4e60c9c..18c2dd72 100644
--- a/roboflow/cli/handlers/image.py
+++ b/roboflow/cli/handlers/image.py
@@ -21,7 +21,14 @@ def upload_image(
     annotation: Annotated[
         Optional[str], typer.Option("-a", "--annotation", help="Path to annotation file (single upload)")
     ] = None,
-    split: Annotated[str, typer.Option("-s", "--split", help="Dataset split")] = "train",
+    split: Annotated[
+        Optional[str],
+        typer.Option(
+            "-s",
+            "--split",
+            help="Override split for all images (default: infer from folder for dirs, 'train' for files)",
+        ),
+    ] = None,
     batch: Annotated[Optional[str], typer.Option("-b", "--batch", help="Batch name")] = None,
     tag: Annotated[Optional[str], typer.Option("-t", "--tag", help="Comma-separated tag names")] = None,
     metadata: Annotated[Optional[str], typer.Option(help="JSON string of key-value metadata")] = None,
@@ -237,7 +244,7 @@ def _handle_upload_single(args, api_key: str, path: str) -> None:  # noqa: ANN00
             image_path=path,
             annotation_path=args.annotation,
             annotation_labelmap=getattr(args, "labelmap", None),
-            split=args.split,
+            split=args.split or "train",
             num_retry_uploads=retries,
             batch_name=args.batch,
             tag_names=tag_names,
diff --git a/roboflow/core/workspace.py b/roboflow/core/workspace.py
index f25292e3..ec2ed474 100644
--- a/roboflow/core/workspace.py
+++ b/roboflow/core/workspace.py
@@ -427,7 +427,8 @@ def upload_dataset(
             is_prediction (bool, optional): whether the annotations provided in the dataset are predictions and not ground truth. Defaults to False.
             use_zip_upload (bool, optional): opt-in to the zip flow for a directory input (the SDK zips it client-side). Ignored when dataset_path is already a `.zip`.
             tags (list[str], optional): zip flow only — tags to apply to the uploaded batch.
-            split (str, optional): zip flow only — dataset split for the uploaded batch.
+            split (str, optional): dataset split for the uploaded batch. In per-image directory
+                uploads, this overrides inferred splits for every image.
             wait (bool, optional): zip flow only — poll for processing completion. Defaults to True.
             poll_interval (float, optional): zip flow only — seconds between status polls.
             poll_timeout (float, optional): zip flow only — total seconds to wait before timing out.
@@ -489,6 +490,9 @@ def upload_dataset(
         is_classification = project.type == "classification"
         parsed_dataset = folderparser.parsefolder(dataset_path, is_classification=is_classification)
         images = parsed_dataset["images"]
+        if split is not None:
+            for image in images:
+                image["split"] = split
 
         location = parsed_dataset["location"]
 
diff --git a/tests/cli/test_image_handler.py b/tests/cli/test_image_handler.py
index 982c4255..c1fb97c7 100644
--- a/tests/cli/test_image_handler.py
+++ b/tests/cli/test_image_handler.py
@@ -345,6 +345,74 @@ def test_zip_upload_flag_defaults_false(self, mock_rf_cls):
             _, kwargs = mock_ws.upload_dataset.call_args
             self.assertEqual(kwargs.get("use_zip_upload"), False)
 
+    @patch("roboflow.Roboflow")
+    def test_upload_directory_omits_default_split_when_not_explicit(self, mock_rf_cls):
+        from roboflow.cli.handlers.image import _handle_upload
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            mock_ws = MagicMock()
+            mock_rf_cls.return_value.workspace.return_value = mock_ws
+
+            args = _make_args(
+                json=True,
+                path=tmpdir,
+                project="proj",
+                annotation=None,
+                split=None,
+                batch=None,
+                tag=None,
+                metadata=None,
+                concurrency=10,
+                retries=0,
+                labelmap=None,
+                is_prediction=False,
+            )
+
+            buf = io.StringIO()
+            old = sys.stdout
+            sys.stdout = buf
+            try:
+                _handle_upload(args)
+            finally:
+                sys.stdout = old
+
+            _, kwargs = mock_ws.upload_dataset.call_args
+            self.assertIsNone(kwargs.get("split"))
+
+    @patch("roboflow.Roboflow")
+    def test_upload_directory_forwards_explicit_split(self, mock_rf_cls):
+        from roboflow.cli.handlers.image import _handle_upload
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            mock_ws = MagicMock()
+            mock_rf_cls.return_value.workspace.return_value = mock_ws
+
+            args = _make_args(
+                json=True,
+                path=tmpdir,
+                project="proj",
+                annotation=None,
+                split="valid",
+                batch=None,
+                tag=None,
+                metadata=None,
+                concurrency=10,
+                retries=0,
+                labelmap=None,
+                is_prediction=False,
+            )
+
+            buf = io.StringIO()
+            old = sys.stdout
+            sys.stdout = buf
+            try:
+                _handle_upload(args)
+            finally:
+                sys.stdout = old
+
+            _, kwargs = mock_ws.upload_dataset.call_args
+            self.assertEqual(kwargs.get("split"), "valid")
+
 
 class TestImageDelete(unittest.TestCase):
     """Test the delete handler."""
diff --git a/tests/test_project.py b/tests/test_project.py
index 7a883232..4c7d2a78 100644
--- a/tests/test_project.py
+++ b/tests/test_project.py
@@ -327,6 +327,15 @@ def test_project_upload_dataset(self):
                 },
                 "assertions": {"upload": {"count": 1, "kwargs": {"batch_name": "test-batch", "num_retry_uploads": 3}}},
             },
+            {
+                "name": "explicit_split_overrides_parsed_directory_splits",
+                "dataset": [
+                    {"file": "image1.jpg", "split": "train"},
+                    {"file": "image2.jpg", "split": "test"},
+                ],
+                "params": {"split": "valid", "num_workers": 1},
+                "assertions": {"upload": {"count": 2, "kwargs": {"split": "valid"}}},
+            },
             {
                 "name": "project_creation",
                 "dataset": None,