diff --git a/README.md b/README.md
index b7910451466..7d31b509819 100644
--- a/README.md
+++ b/README.md
@@ -25,7 +25,7 @@ On OS X (MacPorts):
 sudo port install python27 py27-virtualenv cmake
 ```
 
-On El Capitan, you also have to install openssl:
+On OS X 10.11 (El Capitan), you also have to install openssl:
 
 ``` sh
 brew install openssl