diff --git a/addons/web/static/src/js/views/calendar/calendar_model.js b/addons/web/static/src/js/views/calendar/calendar_model.js
index 5be6b74e1de..c8b9fd574b2 100644
--- a/addons/web/static/src/js/views/calendar/calendar_model.js
+++ b/addons/web/static/src/js/views/calendar/calendar_model.js
@@ -373,6 +373,7 @@ return AbstractModel.extend({
             monthNamesShort: moment.monthsShort(),
             dayNames: moment.weekdays(),
             dayNamesShort: moment.weekdaysShort(),
+            firstDay: moment().startOf('week').isoWeekday(),
         };
     },
     _getRangeDomain: function () {