diff --git a/.github/workflows/eslint.yml b/.github/workflows/eslint.yml
index 3ec533b..aba4a44 100644
--- a/.github/workflows/eslint.yml
+++ b/.github/workflows/eslint.yml
@@ -8,6 +8,12 @@ on:
   workflow_dispatch:
   workflow_call:
 
+
+# Cancel superseded PR runs; master commits use unique SHAs so they still all complete.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.sha }}
+  cancel-in-progress: true
+
 jobs:
   js-and-style:
     name: ESLint
diff --git a/.github/workflows/typos.yml b/.github/workflows/typos.yml
index 9b7d1f3..2985216 100644
--- a/.github/workflows/typos.yml
+++ b/.github/workflows/typos.yml
@@ -8,6 +8,12 @@ on:
   workflow_dispatch:
   workflow_call:
 
+
+# Cancel superseded PR runs; master commits use unique SHAs so they still all complete.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.sha }}
+  cancel-in-progress: true
+
 jobs:
   testing:
     name: Spell Check with Typos
diff --git a/.github/workflows/unit-tests.yml b/.github/workflows/unit-tests.yml
index 9d96eed..5aca731 100644
--- a/.github/workflows/unit-tests.yml
+++ b/.github/workflows/unit-tests.yml
@@ -8,6 +8,12 @@ on:
   workflow_dispatch:
   workflow_call:
 
+
+# Cancel superseded PR runs; master commits use unique SHAs so they still all complete.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.sha }}
+  cancel-in-progress: true
+
 jobs:
   test:
     runs-on: ubuntu-latest