diff --git a/Formula/webp.rb b/Formula/webp.rb
index 81c1e3faed..e534466879 100644
--- a/Formula/webp.rb
+++ b/Formula/webp.rb
@@ -11,6 +11,8 @@ class Webp < Formula
 
   depends_on 'libpng'
   depends_on 'jpeg' => :recommended
+  depends_on 'libtiff' => :optional
+  depends_on 'giflib' => :optional
 
   def install
     ENV.universal_binary if build.universal?