Kleiner Grasbrook is a quarter of Hamburg, Germany within the borough of Hamburg-Mitte. It is situated on the eponymous island between the Northern and Southern branches of the Elbe river, together with the other quarters of Steinwerder, Veddel and Wilhelmsburg. It almost exclusively consists of facilities of the port of Hamburg. The four quarters are technically all islands of their own, as they are all separated by their own dams. In 2020 the population was 1,120.