diff --git a/.github/workflows/copilot-setup-steps.yml b/.github/workflows/copilot-setup-steps.yml
index 730c7d52..9923db62 100644
--- a/.github/workflows/copilot-setup-steps.yml
+++ b/.github/workflows/copilot-setup-steps.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Setup Lean
         uses: Julian/setup-lean@main
diff --git a/.github/workflows/math-check.yml b/.github/workflows/math-check.yml
index 167453ad..963a1b01 100644
--- a/.github/workflows/math-check.yml
+++ b/.github/workflows/math-check.yml
@@ -42,7 +42,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
           submodules: false
@@ -123,7 +123,7 @@ jobs:
     if: github.event_name == 'pull_request'
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
 
@@ -143,7 +143,7 @@ jobs:
     if: github.event_name == 'pull_request'
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
           # We deliberately do not smudge LFS pointers here -- the pre-commit
diff --git a/.github/workflows/wolfram-verification.yml b/.github/workflows/wolfram-verification.yml
index 07a90d1b..aa777cd6 100644
--- a/.github/workflows/wolfram-verification.yml
+++ b/.github/workflows/wolfram-verification.yml
@@ -21,7 +21,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0