diff --git a/triagebot.toml b/triagebot.toml
index d607bd1d712..20056257e59 100644
--- a/triagebot.toml
+++ b/triagebot.toml
@@ -32,6 +32,7 @@ new_pr = true
 
 [assign]
 contributing_url = "https://rust-lang.github.io/cargo/contrib/"
+warn_non_default_branch = true
 
 [assign.owners]
 "*" = ["@ehuss", "@epage", "@weihanglo"]