diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8ef71e81..29954341 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -8,6 +8,9 @@ on:
     branches:
       - '**'
 
+permissions:
+  contents: read
+
 jobs:
   tests:
     name: ${{ matrix.os }} / ${{ matrix.python-version }}