Sint-Maartensdijk is a town in the Dutch province of Zeeland. It is a part of the municipality of Tholen, and lies about 16 km west of Bergen op Zoom.
Sint-Maartensdijk was a separate municipality until 1971, when it was merged with Tholen.
In 2001, the town of Sint-Maartensdijk had 3132 inhabitants. The built-up area of the town was 1.0 km², and contained 1341 residences. The statistical area "Sint-Maartensdijk", which also can include the surrounding countryside, has a population of around 3650.