diff --git a/models/repo_mirror.go b/models/repo_mirror.go
index 447d05530..9f8c9bee6 100644
--- a/models/repo_mirror.go
+++ b/models/repo_mirror.go
@@ -63,7 +63,11 @@ func (m *Mirror) AfterLoad(session *xorm.Session) {
 
 // ScheduleNextUpdate calculates and sets next update time.
 func (m *Mirror) ScheduleNextUpdate() {
-	m.NextUpdateUnix = util.TimeStampNow().AddDuration(m.Interval)
+	if m.Interval != 0 {
+		m.NextUpdateUnix = util.TimeStampNow().AddDuration(m.Interval)
+	} else {
+		m.NextUpdateUnix = 0
+	}
 }
 
 func remoteAddress(repoPath string) (string, error) {
@@ -302,6 +306,7 @@ func MirrorUpdate() {
 
 	if err := x.
 		Where("next_update_unix<=?", time.Now().Unix()).
+		And("next_update_unix!=0").
 		Iterate(new(Mirror), func(idx int, bean interface{}) error {
 			m := bean.(*Mirror)
 			if m.Repo == nil {
diff --git a/options/locale/locale_en-US.ini b/options/locale/locale_en-US.ini
index 6f3234157..a82acc3dd 100644
--- a/options/locale/locale_en-US.ini
+++ b/options/locale/locale_en-US.ini
@@ -524,7 +524,7 @@ create_repo = Create Repository
 default_branch = Default Branch
 mirror_prune = Prune
 mirror_prune_desc = Remove obsolete remote-tracking references
-mirror_interval = Mirror Interval (valid time units are 'h', 'm', 's')
+mirror_interval = Mirror Interval (valid time units are 'h', 'm', 's'). 0 to disable automatic sync.
 mirror_interval_invalid = The mirror interval is not valid.
 mirror_address = Clone From URL
 mirror_address_desc = Include any required authorization credentials in the URL.
diff --git a/routers/repo/setting.go b/routers/repo/setting.go
index ff6b07f8e..61b00d793 100644
--- a/routers/repo/setting.go
+++ b/routers/repo/setting.go
@@ -117,12 +117,16 @@ func SettingsPost(ctx *context.Context, form auth.RepoSettingForm) {
 		}
 
 		interval, err := time.ParseDuration(form.Interval)
-		if err != nil || interval < setting.Mirror.MinInterval {
+		if err != nil && (interval != 0 || interval < setting.Mirror.MinInterval) {
 			ctx.RenderWithErr(ctx.Tr("repo.mirror_interval_invalid"), tplSettingsOptions, &form)
 		} else {
 			ctx.Repo.Mirror.EnablePrune = form.EnablePrune
 			ctx.Repo.Mirror.Interval = interval
-			ctx.Repo.Mirror.NextUpdateUnix = util.TimeStampNow().AddDuration(interval)
+			if interval != 0 {
+				ctx.Repo.Mirror.NextUpdateUnix = util.TimeStampNow().AddDuration(interval)
+			} else {
+				ctx.Repo.Mirror.NextUpdateUnix = 0
+			}
 			if err := models.UpdateMirror(ctx.Repo.Mirror); err != nil {
 				ctx.RenderWithErr(ctx.Tr("repo.mirror_interval_invalid"), tplSettingsOptions, &form)
 				return