diff --git a/notebooks/ipynb_drop_output.py b/notebooks/ipynb_drop_output.py
index df39dcc..42b8d02 100755
--- a/notebooks/ipynb_drop_output.py
+++ b/notebooks/ipynb_drop_output.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """
 Suppress output and prompt numbers in git version control.