diff --git a/tools/preprocess.py b/tools/preprocess.py
index 4c43c2a..0cd3bdf 100755
--- a/tools/preprocess.py
+++ b/tools/preprocess.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 # SPDX-License-Identifier: LGPL-3.0-or-later
 # Copyright (C) 2020 Daniel Thompson