diff --git a/sam2/build_sam.py b/sam2/build_sam.py
index 7346adc0e..813061326 100644
--- a/sam2/build_sam.py
+++ b/sam2/build_sam.py
@@ -5,12 +5,29 @@
 # LICENSE file in the root directory of this source tree.
 
 import logging
+import os
 
+import sam2
 import torch
 from hydra import compose
 from hydra.utils import instantiate
 from omegaconf import OmegaConf
 
+# Check if the user is running Python from the parent directory of the sam2 repo
+# (i.e. the directory where this repo is cloned into) -- this is not supported since
+# it could shadow the sam2 package and cause issues.
+if os.path.isdir(os.path.join(sam2.__path__[0], "sam2")):
+    # If the user has "sam2/sam2" in their path, they are likey importing the repo itself
+    # as "sam2" rather than importing the "sam2" python package (i.e. "sam2/sam2" directory).
+    # This typically happens because the user is running Python from the parent directory
+    # that contains the sam2 repo they cloned.
+    raise RuntimeError(
+        "You're likely running Python from the parent directory of the sam2 repo "
+        "(i.e. the directory where this repo https://github.com/facebookresearch/sam2 is cloned into). "
+        "This is not supported since the sam2 package could be shadowed by the repository name. "
+        "Please run Python from another directory (e.g. your home directory) after installation."
+    )
+
 HF_MODEL_ID_TO_FILENAMES = {
     "facebook/sam2-hiera-tiny": (
         "configs/sam2/sam2_hiera_t.yaml",