diff --git a/.travis.yml b/.travis.yml
index 8c524332..8110adc8 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -19,6 +19,7 @@ before_script:
   - composer install --dev --no-interaction
 
 script:
+  - sh -c "if [ '$TRAVIS_PHP_VERSION' = '5.5' ]; then vendor/bin/phpcs -s --extensions=php --standard=tests/code_sniffer_ruleset.xml phpseclib/; fi"
   - phpunit --verbose --coverage-text --coverage-html code_coverage/
 
 after_success: