diff --git a/Library/Homebrew/dependency_collector.rb b/Library/Homebrew/dependency_collector.rb
index c5a6780676..2601e629c4 100644
--- a/Library/Homebrew/dependency_collector.rb
+++ b/Library/Homebrew/dependency_collector.rb
@@ -18,7 +18,7 @@ require 'set'
 class DependencyCollector
   # Define the languages that we can handle as external dependencies.
   LANGUAGE_MODULES = Set[
-    :chicken, :jruby, :lua, :node, :ocaml, :perl, :python, :rbx, :ruby
+    :chicken, :jruby, :lua, :node, :ocaml, :perl, :python, :python3, :rbx, :ruby
   ].freeze
 
   CACHE = {}