diff --git a/.travis.yml b/.travis.yml
index e7bf93b..fa61b44 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -30,5 +30,12 @@ script:
     && (echo 'Idempotence test: pass' && exit 0)
     || (echo 'Idempotence test: fail' && exit 1)
 
+  # Run the role/playbook a third time, in --check mode.
+  - >
+    ansible-playbook -i tests/inventory tests/$SITE --connection=local --check --sudo
+    | grep -q 'changed=0.*failed=0'
+    && (echo 'Check mode: pass' && exit 0)
+    || (echo 'Check mode: fail' && exit 1)
+
   # Request a page via Apache, to make sure Apache is running and responds.
   - "curl http://localhost/"