diff --git a/ci/travis_osx_install b/ci/travis_osx_install
index 0386e6d7abac452b5c5ca0e598b8e6a0752e59f4..6974147109d184549a5ed349537ad64b9b3dd94f 100755
--- a/ci/travis_osx_install
+++ b/ci/travis_osx_install
@@ -2,6 +2,6 @@
 
 set -x
 
-brew install llvm@5
-brew outdated llvm@5 || brew upgrade llvm@5
+brew install llvm@6
+brew outdated llvm@6 || brew upgrade llvm@6
 
diff --git a/ci/travis_osx_script b/ci/travis_osx_script
index db3992aa8e67530a8903bf77d87f5dac5d48afe8..56cf45cd5fab350a2108bfaed344bdb624f9fd63 100755
--- a/ci/travis_osx_script
+++ b/ci/travis_osx_script
@@ -5,7 +5,7 @@ set -e
 
 mkdir build
 cd build
-cmake .. -DCMAKE_PREFIX_PATH=/usr/local/opt/llvm@5/ -DCMAKE_INSTALL_PREFIX=$(pwd)
+cmake .. -DCMAKE_PREFIX_PATH=/usr/local/opt/llvm@6/ -DCMAKE_INSTALL_PREFIX=$(pwd)
 make VERBOSE=1
 make install