diff --git a/.github/workflows/nightly.yml b/.github/workflows/nightly.yml
index ae166e8469..923ceddca0 100644
--- a/.github/workflows/nightly.yml
+++ b/.github/workflows/nightly.yml
@@ -7,6 +7,10 @@ env:
   RUSTDOCFLAGS: "--cfg docsrs"
   RUSTTOOLCHAIN: "nightly"
 
+concurrency:
+  group: ${{ github.ref }}
+  cancel-in-progress: ${{ github.ref != 'refs/heads/master' }}
+
 jobs:
   quiche:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/stable.yml b/.github/workflows/stable.yml
index bef6186fac..ad5be639f7 100644
--- a/.github/workflows/stable.yml
+++ b/.github/workflows/stable.yml
@@ -6,6 +6,10 @@ env:
   RUSTFLAGS: "-D warnings"
   RUSTTOOLCHAIN: "stable"
 
+concurrency:
+  group: ${{ github.ref }}
+  cancel-in-progress: ${{ github.ref != 'refs/heads/master' }}
+
 jobs:
   quiche:
     runs-on: ubuntu-latest