diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index 64753c2cf38..d0ca14b6c9a 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -104,6 +104,9 @@ jobs:
             @.github/workflows/pytest_args_parallel.txt \
             --junitxml=pytest.xdist.junit.xml \
             -k 'not testsuite'
+        env:
+          OMP_NUM_THREADS: 1
+
       - name: Run pytest with a single worker (for tests marked with needs_solo_run)
         shell: micromamba-shell {0}
         run: |
diff --git a/.github/workflows/pytest.yml b/.github/workflows/pytest.yml
index 8bed78c0a9d..f6a9f65a3c7 100644
--- a/.github/workflows/pytest.yml
+++ b/.github/workflows/pytest.yml
@@ -105,6 +105,8 @@ jobs:
             @.github/workflows/pytest_args_parallel.txt \
             --junitxml=pytest.xdist.junit.xml \
             -k 'not testsuite'
+        env:
+          OMP_NUM_THREADS: 1
 
       - name: Run pytest with a single worker (for tests marked with needs_solo_run)
         run: |