diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 05b7cf29..809ea2c8 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -60,3 +60,5 @@ jobs:
         working-directory: ${{runner.workspace}}/build
         shell: bash
         run: ctest -V
+        env:
+          OMP_NUM_THREADS: 1