diff --git a/tsdb/db.go b/tsdb/db.go
index c44737c69..95250392e 100644
--- a/tsdb/db.go
+++ b/tsdb/db.go
@@ -2077,6 +2077,9 @@ func (db *DB) blockChunkQuerierForRange(mint, maxt int64) (_ []storage.ChunkQuer
 		rh := NewOOORangeHead(db.head, mint, maxt, db.lastGarbageCollectedMmapRef)
 		outOfOrderHeadQuerier, err := NewBlockChunkQuerier(rh, mint, maxt)
 		if err != nil {
+			// If NewBlockQuerier() failed, make sure to clean up the pending read created by NewOOORangeHead.
+			rh.isoState.Close()
+
 			return nil, fmt.Errorf("open block chunk querier for ooo head %s: %w", rh, err)
 		}