diff --git a/Library/Homebrew/os/mac/xcode.rb b/Library/Homebrew/os/mac/xcode.rb
index 91b2c13293..5b4b61e23a 100644
--- a/Library/Homebrew/os/mac/xcode.rb
+++ b/Library/Homebrew/os/mac/xcode.rb
@@ -14,7 +14,7 @@ module OS
         when "10.7"  then "4.6.3"
         when "10.8"  then "5.1.1"
         when "10.9"  then "6.2"
-        when "10.10" then "6.3.2"
+        when "10.10" then "6.4"
         when "10.11" then "7.0"
         else
           # Default to newest known version of Xcode for unreleased OSX versions.