diff --git a/app/assets/javascripts/discourse/components/date-picker.js.es6 b/app/assets/javascripts/discourse/components/date-picker.js.es6
index 758f67622c2..982221fd906 100644
--- a/app/assets/javascripts/discourse/components/date-picker.js.es6
+++ b/app/assets/javascripts/discourse/components/date-picker.js.es6
@@ -21,7 +21,7 @@ export default Ember.Component.extend({
           container: container || this.$()[0],
           bound: container === undefined,
           format: "YYYY-MM-DD",
-          firstDay: moment.localeData().firstDayOfWeek(),
+          firstDay: 1,
           i18n: {
             previousMonth: I18n.t("dates.previous_month"),
             nextMonth: I18n.t("dates.next_month"),