diff --git a/.github/workflows/aead-stream.yml b/.github/workflows/aead-stream.yml
index a09a7fde..4318e260 100644
--- a/.github/workflows/aead-stream.yml
+++ b/.github/workflows/aead-stream.yml
@@ -17,6 +17,11 @@ 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/aes-gcm-siv.yml b/.github/workflows/aes-gcm-siv.yml
index 21c7aa7a..81feb35b 100644
--- a/.github/workflows/aes-gcm-siv.yml
+++ b/.github/workflows/aes-gcm-siv.yml
@@ -17,6 +17,11 @@ 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/aes-gcm.yml b/.github/workflows/aes-gcm.yml
index 0b58fda0..eea761e8 100644
--- a/.github/workflows/aes-gcm.yml
+++ b/.github/workflows/aes-gcm.yml
@@ -17,6 +17,11 @@ 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/aes-siv.yml b/.github/workflows/aes-siv.yml
index fcd7eca4..30d96d56 100644
--- a/.github/workflows/aes-siv.yml
+++ b/.github/workflows/aes-siv.yml
@@ -17,6 +17,11 @@ 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/ascon-aead128.yml b/.github/workflows/ascon-aead128.yml
index b41e8ab1..aeb2dbac 100644
--- a/.github/workflows/ascon-aead128.yml
+++ b/.github/workflows/ascon-aead128.yml
@@ -17,6 +17,11 @@ 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/belt-dwp.yml b/.github/workflows/belt-dwp.yml
index 19e498ec..90e84f9e 100644
--- a/.github/workflows/belt-dwp.yml
+++ b/.github/workflows/belt-dwp.yml
@@ -17,6 +17,11 @@ 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/benches.yml b/.github/workflows/benches.yml
index 494c22b8..6132508b 100644
--- a/.github/workflows/benches.yml
+++ b/.github/workflows/benches.yml
@@ -17,6 +17,11 @@ 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:
     if: false # benches are broken until https://github.com/RustCrypto/AEADs/pull/665 merges
diff --git a/.github/workflows/ccm.yml b/.github/workflows/ccm.yml
index b7630a39..9982df48 100644
--- a/.github/workflows/ccm.yml
+++ b/.github/workflows/ccm.yml
@@ -17,6 +17,11 @@ 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/chacha20poly1305.yml b/.github/workflows/chacha20poly1305.yml
index 240b4b65..8eb3554f 100644
--- a/.github/workflows/chacha20poly1305.yml
+++ b/.github/workflows/chacha20poly1305.yml
@@ -17,6 +17,11 @@ 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/deoxys.yml b/.github/workflows/deoxys.yml
index 7c161a85..ea972479 100644
--- a/.github/workflows/deoxys.yml
+++ b/.github/workflows/deoxys.yml
@@ -17,6 +17,11 @@ 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/eax.yml b/.github/workflows/eax.yml
index fbd87f68..48f97738 100644
--- a/.github/workflows/eax.yml
+++ b/.github/workflows/eax.yml
@@ -17,6 +17,11 @@ 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/mgm.yml b/.github/workflows/mgm.yml
index 8f4a75d8..3d662067 100644
--- a/.github/workflows/mgm.yml
+++ b/.github/workflows/mgm.yml
@@ -17,6 +17,11 @@ 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/ocb3.yml b/.github/workflows/ocb3.yml
index 98ec676e..fa649d2d 100644
--- a/.github/workflows/ocb3.yml
+++ b/.github/workflows/ocb3.yml
@@ -17,6 +17,11 @@ 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 961bf75c..190e66b7 100644
--- a/.github/workflows/workspace.yml
+++ b/.github/workflows/workspace.yml
@@ -12,6 +12,11 @@ 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:
   rustfmt:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/xaes-256-gcm.yml b/.github/workflows/xaes-256-gcm.yml
index d803c804..5b1e1399 100644
--- a/.github/workflows/xaes-256-gcm.yml
+++ b/.github/workflows/xaes-256-gcm.yml
@@ -17,6 +17,11 @@ 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