diff --git a/models/issue_milestone.go b/models/issue_milestone.go
index 1587e5e34..df2f30fb3 100644
--- a/models/issue_milestone.go
+++ b/models/issue_milestone.go
@@ -306,7 +306,11 @@ func ChangeMilestoneStatus(m *Milestone, isClosed bool) (err error) {
 	}
 
 	m.IsClosed = isClosed
-	if _, err := sess.ID(m.ID).Cols("is_closed").Update(m); err != nil {
+	if isClosed {
+		m.ClosedDateUnix = timeutil.TimeStampNow()
+	}
+
+	if _, err := sess.ID(m.ID).Cols("is_closed", "closed_date_unix").Update(m); err != nil {
 		return err
 	}