diff --git a/ui/jquery.ui.datepicker.js b/ui/jquery.ui.datepicker.js
index 27ffadbff00..d1d8a4d11ad 100644
--- a/ui/jquery.ui.datepicker.js
+++ b/ui/jquery.ui.datepicker.js
@@ -982,7 +982,7 @@ $.extend(Datepicker.prototype, {
 		var getName = function(match, shortNames, longNames) {
 			var names = (lookAhead(match) ? longNames : shortNames);
 			for (var i = 0; i < names.length; i++) {
-				if (value.substr(iValue, names[i].length) == names[i]) {
+				if (value.substr(iValue, names[i].length).toLowerCase() == names[i].toLowerCase()) {
 					iValue += names[i].length;
 					return i + 1;
 				}