diff --git a/Library/Homebrew/env_config.rb b/Library/Homebrew/env_config.rb
index 63f97e7df17f1..eb3752bde70c3 100644
--- a/Library/Homebrew/env_config.rb
+++ b/Library/Homebrew/env_config.rb
@@ -450,7 +450,7 @@ module EnvConfig
       },
       HOMEBREW_TEST_TIMEOUT_SECS:                {
         description: "If set, use this value in seconds as the timeout for formula test runs.",
-        default:     600,
+        default:     300,
       },
       HOMEBREW_UPDATE_TO_TAG:                    {
         description: "If set, always use the latest stable tag (even if developer commands " \