diff --git a/.github/workflows/ci_tests.yml b/.github/workflows/ci_tests.yml
index 4ee87fa9..e52b0a3c 100644
--- a/.github/workflows/ci_tests.yml
+++ b/.github/workflows/ci_tests.yml
@@ -7,6 +7,10 @@ on:
     # run every Monday at 6am UTC
     - cron: '0 6 * * 1'
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 env:
   SETUP_XVFB: True  # avoid issues if mpl tries to open a GUI window
   TOXARGS: '-v'