diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 3980f1ee..d53c045d 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -7,6 +7,12 @@ on:
   # Allow manually triggering the workflow.
   workflow_dispatch:
 
+# Cancels all previous workflow runs for the same branch that have not yet completed.
+concurrency:
+  # The concurrency group contains the workflow name and the branch name.
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   bundle:
     # Don't run on forks.
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index a0f2abc1..e22bd055 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -9,6 +9,12 @@ on:
   # Allow manually triggering the workflow.
   workflow_dispatch:
 
+# Cancels all previous workflow runs for the same branch that have not yet completed.
+concurrency:
+  # The concurrency group contains the workflow name and the branch name.
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   lint:
     name: Run style linter