diff --git a/.travis.yml b/.travis.yml
index 2e385e3..44dd38f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -26,12 +26,12 @@ matrix:
     - os: osx
       osx_image: xcode8
       env:
-        - MATRIX_EVAL="brew install gcc6 && CC=gcc-6 && CXX=g++-6"
+        - MATRIX_EVAL="brew update && brew install gcc6 && CC=gcc-6 && CXX=g++-6"
         
     - os: osx
       osx_image: xcode8
       env:
-        - MATRIX_EVAL="brew install gcc && CC=gcc-7 && CXX=g++-7"
+        - MATRIX_EVAL="brew update && brew install gcc && CC=gcc-7 && CXX=g++-7"
 
 before_install:
   - eval "${MATRIX_EVAL}"