diff --git a/Library/Homebrew/sandbox.rb b/Library/Homebrew/sandbox.rb
index b1493369a1..dece2e4a58 100644
--- a/Library/Homebrew/sandbox.rb
+++ b/Library/Homebrew/sandbox.rb
@@ -8,7 +8,7 @@ class Sandbox
   ].freeze
 
   def self.available?
-    OS.mac? && File.executable?(SANDBOX_EXEC)
+    OS.mac? && OS::Mac.version >= "10.6" && File.executable?(SANDBOX_EXEC)
   end
 
   def self.formula?(formula)