diff --git a/Library/Homebrew/github_runner_matrix.rb b/Library/Homebrew/github_runner_matrix.rb
index c0acdba0cf..2ebb435ab1 100644
--- a/Library/Homebrew/github_runner_matrix.rb
+++ b/Library/Homebrew/github_runner_matrix.rb
@@ -141,7 +141,7 @@ class GitHubRunnerMatrix
       runner, timeout = if use_github_runner && github_runner_available
         ["macos-#{version}", GITHUB_ACTIONS_RUNNER_TIMEOUT]
       else
-        ["#{version}#{ephemeral_suffix}", runner_timeout]
+        ["#{version}-x86_64#{ephemeral_suffix}", runner_timeout]
       end
 
       # macOS 12-x86_64 is usually slower.