Oostburg (population: 18,174) is a town in the southwestern Netherlands, in the province of Zeeland. The former municipality covers an area of 224.93 km² (of which 1.05 km² water).
The former municipality of Oostburg also includes the following towns, villages and townships: Breskens, Cadzand, Groede, Hoofdplaat, IJzendijke, Nieuwvliet, Schoondijke, Waterlandkerkje, Zuidzande; all are now part of Sluis.
.