diff --git a/pre_commit/languages/pygrep.py b/pre_commit/languages/pygrep.py
index ec55560..44e08a1 100644
--- a/pre_commit/languages/pygrep.py
+++ b/pre_commit/languages/pygrep.py
@@ -98,7 +98,7 @@ def run_hook(
         color: bool,
 ) -> tuple[int, bytes]:
     cmd = (sys.executable, '-m', __name__, *args, entry)
-    return xargs(cmd, file_args, color=color)
+    return xargs(cmd, file_args, color=color, env={ "PYTHONPATH": ':'.join(sys.path) })
 
 
 def main(argv: Sequence[str] | None = None) -> int: