diff --git a/.github/workflows/automerge.yml b/.github/workflows/automerge.yml
index c4165ba31..6d079b38a 100644
--- a/.github/workflows/automerge.yml
+++ b/.github/workflows/automerge.yml
@@ -23,7 +23,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: automerge
-        uses: pascalgn/automerge-action@v0.12.0
+        uses: pascalgn/automerge-action@c9bd1823770819dc8fb8a5db2d11a3a95fbe9b07 # tag=v0.12.0
         env:
           # Allows this merge to trigger other actions
           GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
diff --git a/.github/workflows/pr-auditor.yml b/.github/workflows/pr-auditor.yml
index 3edc2741b..e455376b7 100644
--- a/.github/workflows/pr-auditor.yml
+++ b/.github/workflows/pr-auditor.yml
@@ -7,9 +7,9 @@ jobs:
   run:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@ec3a7ce113134d7a93b817d10a8272cb61118579 # tag=v2
         with: { repository: 'sourcegraph/sourcegraph' }
-      - uses: actions/setup-go@v2
+      - uses: actions/setup-go@bfdd3570ce990073878bf10f6b2d79082de49492 # tag=v2
         with: { go-version: '1.17' }
 
       - run: ./dev/pr-auditor/check-pr.sh
diff --git a/.github/workflows/update-tags.yml b/.github/workflows/update-tags.yml
index 09d3b7f6a..f0453f74b 100644
--- a/.github/workflows/update-tags.yml
+++ b/.github/workflows/update-tags.yml
@@ -11,8 +11,8 @@ jobs:
   dispatch:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-go@v2
+      - uses: actions/checkout@ec3a7ce113134d7a93b817d10a8272cb61118579 # tag=v2
+      - uses: actions/setup-go@bfdd3570ce990073878bf10f6b2d79082de49492 # tag=v2
         with:
           go-version: '^1.14'
 
@@ -20,7 +20,7 @@ jobs:
       - name: Pin tags to ${{ github.event.inputs.semver }}
         run: tools/update-docker-tags.sh "${{ github.event.inputs.semver }}"
       - name: Open pull request
-        uses: peter-evans/create-pull-request@v3
+        uses: peter-evans/create-pull-request@18f7dc018cc2cd597073088f7c7591b9d1c02672 # tag=v3
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
           base: ${{ github.event.inputs.branch }}