diff --git a/.github/workflows/sorbet.yml b/.github/workflows/sorbet.yml
index e26cd01fb6..4f4c9d61dc 100644
--- a/.github/workflows/sorbet.yml
+++ b/.github/workflows/sorbet.yml
@@ -13,7 +13,7 @@ on:
 jobs:
   tapioca:
     if: github.repository == 'Homebrew/brew'
-    runs-on: macos-latest
+    runs-on: macos-11.0
     steps:
       - name: Set up Homebrew
         id: set-up-homebrew