diff --git a/CHANGELOG.md b/CHANGELOG.md
index 984bb80b92d..7e32d241d49 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,6 +21,7 @@
 * [CHANGE] Metric `cortex_overrides_last_reload_successful` has been renamed to `cortex_runtime_config_last_reload_successful`. #2874
 * [CHANGE] HipChat support has been removed from the alertmanager (because removed from the Prometheus upstream too). #2902
 * [CHANGE] Add constant label `name` to metric `cortex_cache_request_duration_seconds`. #2903
+* [CHANGE] Add `user` label to metric `cortex_query_frontend_queue_length`. #2939
 * [FEATURE] Introduced `ruler.for-outage-tolerance`, Max time to tolerate outage for restoring "for" state of alert. #2783
 * [FEATURE] Introduced `ruler.for-grace-period`, Minimum duration between alert and restored "for" state. This is maintained only for alerts with configured "for" time greater than grace period. #2783
 * [FEATURE] Introduced `ruler.resend-delay`, Minimum amount of time to wait before resending an alert to Alertmanager. #2783
diff --git a/pkg/querier/frontend/frontend.go b/pkg/querier/frontend/frontend.go
index f629a0aafe5..d6beed38322 100644
--- a/pkg/querier/frontend/frontend.go
+++ b/pkg/querier/frontend/frontend.go
@@ -71,7 +71,7 @@ type Frontend struct {
 
 	// Metrics.
 	queueDuration prometheus.Histogram
-	queueLength   prometheus.Gauge
+	queueLength   *prometheus.GaugeVec
 }
 
 type request struct {
@@ -96,11 +96,11 @@ func New(cfg Config, log log.Logger, registerer prometheus.Registerer) (*Fronten
 			Help:      "Time spend by requests queued.",
 			Buckets:   prometheus.DefBuckets,
 		}),
-		queueLength: promauto.With(registerer).NewGauge(prometheus.GaugeOpts{
+		queueLength: promauto.With(registerer).NewGaugeVec(prometheus.GaugeOpts{
 			Namespace: "cortex",
 			Name:      "query_frontend_queue_length",
 			Help:      "Number of queries in the queue.",
-		}),
+		}, []string{"user"}),
 		connectedClients: atomic.NewInt32(0),
 	}
 	f.cond = sync.NewCond(&f.mtx)
@@ -363,7 +363,7 @@ func (f *Frontend) queueRequest(ctx context.Context, req *request) error {
 
 	select {
 	case queue <- req:
-		f.queueLength.Add(1)
+		f.queueLength.WithLabelValues(userID).Inc()
 		f.cond.Broadcast()
 		return nil
 	default:
@@ -416,7 +416,7 @@ FindQueue:
 			f.cond.Broadcast()
 
 			f.queueDuration.Observe(time.Since(request.enqueueTime).Seconds())
-			f.queueLength.Add(-1)
+			f.queueLength.WithLabelValues(userID).Dec()
 			request.queueSpan.Finish()
 
 			// Ensure the request has not already expired.