diff --git a/.gitlab/ci/ubuntu1604.yml b/.gitlab/ci/ubuntu1604.yml
index d0adead93..3fa967aab 100644
--- a/.gitlab/ci/ubuntu1604.yml
+++ b/.gitlab/ci/ubuntu1604.yml
@@ -13,6 +13,8 @@ build:ubuntu1604_gcc5:
     - .cmake_build_linux
     - .only-default
   variables:
+    CC: "gcc-5"
+    CXX: "g++-5"
     CMAKE_BUILD_TYPE: RelWithDebInfo
     VTKM_SETTINGS: "cuda+pascal"
 
@@ -64,6 +66,8 @@ build:ubuntu1604_gcc48:
     - .cmake_build_linux
     - .only-default
   variables:
+    CC: "gcc-4.8"
+    CXX: "g++-4.8"
     CMAKE_BUILD_TYPE: Release
     #custom openmpi install location
     CMAKE_PREFIX_PATH: "/opt/openmpi/"
@@ -108,6 +112,8 @@ build:ubuntu1604_clang5:
     - .cmake_build_linux
     - .only-default
   variables:
+    CC: "clang-5.0"
+    CXX: "clang++-5.0"
     CMAKE_BUILD_TYPE: Debug
     VTKM_SETTINGS: "tbb+static+64bit_floats"