diff --git a/src/west/manifest.py b/src/west/manifest.py
index 500f348e..2e785c0d 100644
--- a/src/west/manifest.py
+++ b/src/west/manifest.py
@@ -2432,6 +2432,10 @@ def _load_project(self, pd: Dict, url_bases: Dict[str, str],
                             f'normalizes to {ret_norm}, which escapes '
                             f'the workspace topdir')
 
+        if os.path.commonpath([ret_norm, util.WEST_DIR]) != '':
+            self._malformed(f'project "{name}" path {ret.path} '
+                            f'is in the {util.WEST_DIR} directory')
+
         return ret
 
     def _validate_project_groups(self, project_name: str,