diff --git a/moment/moment-tests.ts b/moment/moment-tests.ts
index 5150f7ebc4..e86989eed5 100644
--- a/moment/moment-tests.ts
+++ b/moment/moment-tests.ts
@@ -102,6 +102,7 @@ var getHours: number = moment().hours();
 var getDate: number = moment().date();
 var getDay: number = moment().day();
 var getMonth: number = moment().month();
+var getQuater: number = moment().quarter();
 var getYear: number = moment().year();
 
 moment().hours(0).minutes(0).seconds(0).milliseconds(0);
diff --git a/moment/moment.d.ts b/moment/moment.d.ts
index a920b57acf..20e921c324 100644
--- a/moment/moment.d.ts
+++ b/moment/moment.d.ts
@@ -1,7 +1,8 @@
-// Type definitions for Moment.js 2.4.0
+// Type definitions for Moment.js 2.5.0
 // Project: https://github.com/timrwood/moment
 // Definitions by: Michael Lakerveld <https://github.com/Lakerfield>
 // 		2.4.0 Aaron King <https://github.com/kingdango>
+// 		2.5.0 Hiroki Horiuchi <https://github.com/horiuchi>
 // DefinitelyTyped: https://github.com/borisyankov/DefinitelyTyped
 
 
@@ -81,6 +82,7 @@ interface Moment {
 
     year(y: number): Moment;
     year(): number;
+    quarter(): number;
     month(M: number): Moment;
     month(M: string): Moment;
     month(): number;