Gellersen is a Samtgemeinde ("collective municipality") in the district of Lüneburg, in Lower Saxony, Germany. It is situated approximately 5 km west of Lüneburg. Its seat is in the village Reppenstedt.
The Samtgemeinde Gellersen consists of the following municipalities:
Coordinates: 53°14′52″N 10°21′10″E / 53.24778°N 10.35278°E