diff --git a/.github/workflows/check-unsafe-flags.yml b/.github/workflows/check-unsafe-flags.yml
index 348f4430..39bb776e 100644
--- a/.github/workflows/check-unsafe-flags.yml
+++ b/.github/workflows/check-unsafe-flags.yml
@@ -6,6 +6,10 @@ on:
   pull_request:
     branches: [ "main" ]
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   dump-package-check:
     name: Dump Swift package (authoritative) and scan JSON
diff --git a/.github/workflows/claude-code-review.yml b/.github/workflows/claude-code-review.yml
index 9adfd522..48bb046b 100644
--- a/.github/workflows/claude-code-review.yml
+++ b/.github/workflows/claude-code-review.yml
@@ -10,6 +10,10 @@ on:
     #   - "src/**/*.js"
     #   - "src/**/*.jsx"
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   claude-review:
     # Optional: Filter by PR author
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 6d1351bf..7f6cd451 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -21,6 +21,13 @@ on:
   schedule:
     - cron: '20 11 * * 3'
 
+concurrency:
+  # event_name is part of the key so the weekly scheduled scan and a push scan of
+  # the same branch never cancel each other; within one event type, only the
+  # newest run of a branch survives.
+  group: ${{ github.workflow }}-${{ github.event_name }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   analyze:
     name: Analyze
diff --git a/.github/workflows/examples.yml b/.github/workflows/examples.yml
index ed403c33..239ee1e3 100644
--- a/.github/workflows/examples.yml
+++ b/.github/workflows/examples.yml
@@ -4,6 +4,10 @@ on:
   pull_request:
     branches: [main]
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
+
 env:
   PACKAGE_NAME: MistKit
 
diff --git a/.github/workflows/swift-source-compat.yml b/.github/workflows/swift-source-compat.yml
index 4ab0b691..3c6f610a 100644
--- a/.github/workflows/swift-source-compat.yml
+++ b/.github/workflows/swift-source-compat.yml
@@ -6,6 +6,10 @@ on:
   pull_request:
   workflow_dispatch:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   swift-source-compat-suite:
     name: Test Swift ${{ matrix.container }} For Source Compatibility Suite