diff --git a/tools/travis_build.sh b/tools/travis_build.sh
index f45875ae..7ed37c56 100644
--- a/tools/travis_build.sh
+++ b/tools/travis_build.sh
@@ -1,3 +1,4 @@
+#!/usr/bin/sh
 ./header.py "Run all tests with minimum dependencies"
 nosetests --exe -v skimage
 
diff --git a/tools/travis_setup.sh b/tools/travis_setup.sh
index c6d8c566..ad740a69 100644
--- a/tools/travis_setup.sh
+++ b/tools/travis_setup.sh
@@ -1,3 +1,4 @@
+#!/usr/bin/sh
 travis_retry pip install wheel flake8 coveralls nose
 
 # on Python 2.7, use the system versions of numpy, scipy, and matplotlib