diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index abbccd8d..c6e1e1e6 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -79,6 +79,8 @@ jobs:
         env:
           MKLROOT: ~/.local
           MACOSX_DEPLOYMENT_TARGET: '10.9'
+          CC: gcc-9
+          CXX: g++-9
         run: |
           mkdir build
           cd build
@@ -91,6 +93,8 @@ jobs:
         env:
           MKLROOT: ~/.local
           MACOSX_DEPLOYMENT_TARGET: '10.9'
+          CC: gcc-9
+          CXX: g++-9
         run: |
           mkdir build
           cd build
@@ -102,6 +106,8 @@ jobs:
         if: matrix.parallel == 'serial' && matrix.os == 'ubuntu-22.04'
         env:
           MKLROOT: ~/.local
+          CC: gcc-9
+          CXX: g++-9
         run: |
           mkdir build_test
           cd build_test