Oostdijk is a hamlet in the Dutch province of South Holland.

It is a part of the municipality of Goeree-Overflakkee, and lies about 13 km west of Hellevoetsluis.

It was first mentioned in 1515 as "gelegen in Westvoirne bijder Goederee inder banne vanden oestdijck", and means "eastern dike".

[1] Oostdijk is not a statistical entity,[2] It is considered part of Goedereede.

[3] This South Holland location article is a stub.