diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index adb3c19e..13ae41ba 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checking out code from GitHub
-        uses: actions/checkout@v1
+        uses: actions/checkout@v2.3.1
       - name: Set up Python 3.7
         uses: actions/setup-python@v1
         with:
@@ -41,7 +41,7 @@ jobs:
         python: [3.7, 3.8]
     steps:
       - name: Checking out code from GitHub
-        uses: actions/checkout@v1
+        uses: actions/checkout@v2.3.1
       - name: Set up Python ${{ matrix.python }}
         uses: actions/setup-python@v1
         with:
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index b8b4fadd..2e5f4d1b 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v2.3.1
     - name: Set up Python
       uses: actions/setup-python@v1
       with: