diff --git a/.travis.yml b/.travis.yml
index 2327f9e5d1..237f468d91 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -19,6 +19,8 @@ before_install:
   - $CXX --version
   - $CC --version
 
+  - if [ $TRAVIS_OS_NAME == linux ]; then sudo apt-get update; fi
+
   # OS X: update brew cache:
   - if [ $TRAVIS_OS_NAME == osx ]; then brew update; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" && "$CC" == "gcc" ]]; then CC=gcc-4.9; fi