diff --git a/lib/tests/modules.sh b/lib/tests/modules.sh
index 2f36d6107ca4..1c6a907b7938 100755
--- a/lib/tests/modules.sh
+++ b/lib/tests/modules.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/usr/bin/env bash
 #
 # This script is used to test that the module system is working as expected.
 # By default it test the version of nixpkgs which is defined in the NIX_PATH.