diff --git a/.github/workflows/unittest-macos.yml b/.github/workflows/unittest-macos.yml
index 0a9d31bd84..b0bc4b2727 100644
--- a/.github/workflows/unittest-macos.yml
+++ b/.github/workflows/unittest-macos.yml
@@ -15,7 +15,7 @@ jobs:
   build:
     name: MacOS Unit Test
     if: ${{ github.repository == 'lammps/lammps' }}
-    runs-on: macos-latest
+    runs-on: macos-13
     env:
       CCACHE_DIR: ${{ github.workspace }}/.ccache