diff --git a/lib/linguist/heuristics.rb b/lib/linguist/heuristics.rb
index 48b7e54f..ad4f4504 100644
--- a/lib/linguist/heuristics.rb
+++ b/lib/linguist/heuristics.rb
@@ -354,7 +354,7 @@ module Linguist
     disambiguate ".r" do |data|
       if /\bRebol\b/i.match(data)
         Language["Rebol"]
-      elsif data.include?("<-")
+      elsif /<-|^\s*#/.match(data)
         Language["R"]
       end
     end