diff --git a/.travis.yml b/.travis.yml
index e11b038a3c..bfb3256c77 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,6 +5,7 @@ python:
     - "3.4"
 install:
     - pip install -q -r src/requirements.txt
+    - npm install less@2.5.0
 before_script:
     - cd src
     - flake8 --ignore=E123,F403,F401,N802,C901,W503 .