diff --git a/butterfly/static/coffees/term.coffee b/butterfly/static/coffees/term.coffee
index f854d0c..008abfc 100644
--- a/butterfly/static/coffees/term.coffee
+++ b/butterfly/static/coffees/term.coffee
@@ -1297,7 +1297,7 @@ class Terminal
                     else
                          key = String.fromCharCode(29) if ev.keyCode is 221
 
-                else if ev.altKey
+                else if (ev.altKey and 'Mac' not in navigator.platform) or (ev.metaKey and 'Mac' in navigator.platform)
                     if ev.keyCode >= 65 and ev.keyCode <= 90
                         key = "\x1b" + String.fromCharCode(ev.keyCode + 32)
                     else if ev.keyCode is 192
diff --git a/butterfly/static/javascripts/main.js b/butterfly/static/javascripts/main.js
index 5c4ed89..87539a1 100644
--- a/butterfly/static/javascripts/main.js
+++ b/butterfly/static/javascripts/main.js
@@ -1193,7 +1193,7 @@ Terminal = (function() {
               key = String.fromCharCode(29);
             }
           }
-        } else if (ev.altKey) {
+        } else if ((ev.altKey && __indexOf.call(navigator.platform, 'Mac') < 0) || (ev.metaKey && __indexOf.call(navigator.platform, 'Mac') >= 0)) {
           if (ev.keyCode >= 65 && ev.keyCode <= 90) {
             key = "\x1b" + String.fromCharCode(ev.keyCode + 32);
           } else if (ev.keyCode === 192) {