diff --git a/storage/remote/queue_manager.go b/storage/remote/queue_manager.go
index e4a289473..33f8c4e9a 100644
--- a/storage/remote/queue_manager.go
+++ b/storage/remote/queue_manager.go
@@ -126,7 +126,7 @@ var (
 			Namespace: namespace,
 			Subsystem: subsystem,
 			Name:      "queue_highest_sent_timestamp",
-			Help:      "Timestamp from a WAL sample, the highest timestamp successfully sent by this queue.",
+			Help:      "Timestamp from a WAL sample, the highest timestamp successfully sent by this queue, in seconds since epoch.",
 		},
 		[]string{queue},
 	)
@@ -524,7 +524,7 @@ func (t *QueueManager) setHighestSentTimestamp(highest int64) {
 	defer t.timestampLock.Unlock()
 	if highest > t.highestSentTimestamp {
 		t.highestSentTimestamp = highest
-		t.highestSentTimestampMetric.Set(float64(t.highestSentTimestamp))
+		t.highestSentTimestampMetric.Set(float64(t.highestSentTimestamp) / 1000.)
 	}
 }
 
diff --git a/storage/remote/storage.go b/storage/remote/storage.go
index 428773c05..062a5c949 100644
--- a/storage/remote/storage.go
+++ b/storage/remote/storage.go
@@ -71,7 +71,7 @@ func NewStorage(l log.Logger, reg prometheus.Registerer, stCallback startTimeCal
 		}),
 		highestTimestampMetric: prometheus.NewGauge(prometheus.GaugeOpts{
 			Name: "prometheus_remote_storage_highest_timestamp_in",
-			Help: "Highest timestamp that has come into the remote storage via the Appender interface.",
+			Help: "Highest timestamp that has come into the remote storage via the Appender interface, in seconds since epoch.",
 		}),
 	}
 	reg.MustRegister(s.samplesInMetric)
diff --git a/storage/remote/write.go b/storage/remote/write.go
index f44662af1..5038425a6 100644
--- a/storage/remote/write.go
+++ b/storage/remote/write.go
@@ -55,7 +55,7 @@ func (t *timestampTracker) Commit() error {
 	defer t.storage.highestTimestampMtx.Unlock()
 	if t.highestTimestamp > t.storage.highestTimestamp {
 		t.storage.highestTimestamp = t.highestTimestamp
-		t.storage.highestTimestampMetric.Set(float64(t.highestTimestamp))
+		t.storage.highestTimestampMetric.Set(float64(t.highestTimestamp) / 1000.)
 	}
 	return nil
 }