diff --git a/.github/workflows/aarch64-dit.yml b/.github/workflows/aarch64-dit.yml
index 4eeaafb5..c2a9bd02 100644
--- a/.github/workflows/aarch64-dit.yml
+++ b/.github/workflows/aarch64-dit.yml
@@ -19,6 +19,11 @@ env:
   CARGO_INCREMENTAL: 0
   RUSTFLAGS: "-Dwarnings"
 
+# Cancels CI jobs when new commits are pushed to a PR branch
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   macos:
     strategy:
diff --git a/.github/workflows/blobby.yml b/.github/workflows/blobby.yml
index 5d262a88..95ca6cef 100644
--- a/.github/workflows/blobby.yml
+++ b/.github/workflows/blobby.yml
@@ -19,6 +19,11 @@ env:
   CARGO_INCREMENTAL: 0
   RUSTFLAGS: "-Dwarnings"
 
+# Cancels CI jobs when new commits are pushed to a PR branch
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   test:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/block-buffer.yml b/.github/workflows/block-buffer.yml
index 5ee8e0d5..3eac1788 100644
--- a/.github/workflows/block-buffer.yml
+++ b/.github/workflows/block-buffer.yml
@@ -19,6 +19,11 @@ env:
   CARGO_INCREMENTAL: 0
   RUSTFLAGS: "-Dwarnings"
 
+# Cancels CI jobs when new commits are pushed to a PR branch
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   build:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/block-padding.yml b/.github/workflows/block-padding.yml
index 447f98da..329e4233 100644
--- a/.github/workflows/block-padding.yml
+++ b/.github/workflows/block-padding.yml
@@ -19,6 +19,11 @@ env:
   CARGO_INCREMENTAL: 0
   RUSTFLAGS: "-Dwarnings"
 
+# Cancels CI jobs when new commits are pushed to a PR branch
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   build:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/cmov.yml b/.github/workflows/cmov.yml
index 453eda95..b2e04f57 100644
--- a/.github/workflows/cmov.yml
+++ b/.github/workflows/cmov.yml
@@ -20,6 +20,11 @@ env:
   CARGO_INCREMENTAL: 0
   RUSTFLAGS: "-Dwarnings"
 
+# Cancels CI jobs when new commits are pushed to a PR branch
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   minimal-versions:
     uses: RustCrypto/actions/.github/workflows/minimal-versions.yml@master
diff --git a/.github/workflows/cpufeatures.yml b/.github/workflows/cpufeatures.yml
index 89c4e5f4..2f83deee 100644
--- a/.github/workflows/cpufeatures.yml
+++ b/.github/workflows/cpufeatures.yml
@@ -19,6 +19,11 @@ env:
   CARGO_INCREMENTAL: 0
   RUSTFLAGS: "-Dwarnings"
 
+# Cancels CI jobs when new commits are pushed to a PR branch
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   minimal-versions:
     uses: RustCrypto/actions/.github/workflows/minimal-versions.yml@master
diff --git a/.github/workflows/dbl.yml b/.github/workflows/dbl.yml
index 2fe441ad..8bf1d05c 100644
--- a/.github/workflows/dbl.yml
+++ b/.github/workflows/dbl.yml
@@ -20,6 +20,11 @@ env:
   CARGO_INCREMENTAL: 0
   RUSTFLAGS: "-Dwarnings"
 
+# Cancels CI jobs when new commits are pushed to a PR branch
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   build:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/digest-io.yml b/.github/workflows/digest-io.yml
index e27f6e64..73fb5db6 100644
--- a/.github/workflows/digest-io.yml
+++ b/.github/workflows/digest-io.yml
@@ -19,6 +19,11 @@ env:
   CARGO_INCREMENTAL: 0
   RUSTFLAGS: "-Dwarnings"
 
+# Cancels CI jobs when new commits are pushed to a PR branch
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   minimal-versions:
     uses: RustCrypto/actions/.github/workflows/minimal-versions.yml@master
diff --git a/.github/workflows/fiat-constify.yml b/.github/workflows/fiat-constify.yml
index e7afbf2c..d406f786 100644
--- a/.github/workflows/fiat-constify.yml
+++ b/.github/workflows/fiat-constify.yml
@@ -20,6 +20,11 @@ env:
   CARGO_INCREMENTAL: 0
   RUSTFLAGS: "-Dwarnings"
 
+# Cancels CI jobs when new commits are pushed to a PR branch
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   test:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/hex-literal.yml b/.github/workflows/hex-literal.yml
index a3c3ece2..d48466a1 100644
--- a/.github/workflows/hex-literal.yml
+++ b/.github/workflows/hex-literal.yml
@@ -19,6 +19,11 @@ env:
   CARGO_INCREMENTAL: 0
   RUSTFLAGS: "-Dwarnings"
 
+# Cancels CI jobs when new commits are pushed to a PR branch
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   build:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/inout.yml b/.github/workflows/inout.yml
index dd0d1536..3d892289 100644
--- a/.github/workflows/inout.yml
+++ b/.github/workflows/inout.yml
@@ -19,6 +19,11 @@ env:
   CARGO_INCREMENTAL: 0
   RUSTFLAGS: "-Dwarnings"
 
+# Cancels CI jobs when new commits are pushed to a PR branch
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   build:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/opaque-debug.yml b/.github/workflows/opaque-debug.yml
index ba95b500..71ec14de 100644
--- a/.github/workflows/opaque-debug.yml
+++ b/.github/workflows/opaque-debug.yml
@@ -19,6 +19,11 @@ env:
   CARGO_INCREMENTAL: 0
   RUSTFLAGS: "-Dwarnings"
 
+# Cancels CI jobs when new commits are pushed to a PR branch
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   build:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/workspace.yml b/.github/workflows/workspace.yml
index 43f82147..2d476480 100644
--- a/.github/workflows/workspace.yml
+++ b/.github/workflows/workspace.yml
@@ -12,6 +12,11 @@ on:
 permissions:
   contents: read
 
+# Cancels CI jobs when new commits are pushed to a PR branch
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   clippy:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/zeroize.yml b/.github/workflows/zeroize.yml
index 6726aaf2..aae5a887 100644
--- a/.github/workflows/zeroize.yml
+++ b/.github/workflows/zeroize.yml
@@ -20,6 +20,11 @@ env:
   CARGO_INCREMENTAL: 0
   RUSTFLAGS: "-Dwarnings"
 
+# Cancels CI jobs when new commits are pushed to a PR branch
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   build:
     runs-on: ubuntu-latest