Oldendorf is a former Samtgemeinde ("collective municipality") in the district of Stade, in Lower Saxony, Germany. Its seat was in the village Oldendorf. It was disbanded on 1 January 2014, when it was merged with the Samtgemeinde Himmelpforten to form the new Samtgemeinde Oldendorf-Himmelpforten.
The Samtgemeinde Oldendorf consisted of the following municipalities:
Coordinates: 53°34′44″N 9°15′54″E / 53.579°N 9.265°E