Zwartsluis is a small city in the Dutch province of Overijssel. It is located in the municipality of Zwartewaterland, at the mouth of the Zwarte Water river and the Meppelerdiep canal [nl].

Zwartsluis's history started in the Eighty Years' War (1568–1648): it developed around the Swartersluys fortress, which controlled traffic on the Zwartewater inlet leading to Hasselt and Zwolle. Zwartsluis attracted some trade and a fishing fleet in later centuries. Zwartsluis also served as a consolidation point for the peat-fuel trade, but was surpassed in importance by its neighbours, especially downstream Genemuiden.

The Dutch Reformed Church of Zwartsluis is a historic Dutch Reformed church building located on the Kerkstraat and the organ in the church is a designated Rijksmonument.

The town is home to many recreational boats, as well as a heritage fleet of fishing and cargo vessels. The Arembergergracht canal links the town with the Beulaker and Belter lakes and a multitude of smaller bodies of water just north, created by peat digging.

Zwartsluis was a separate municipality until 2001, when it became a part of Zwartewaterland.

• Stieneke van der Graaf (born 1984), politician (MP)

• Media related to Zwartsluis at Wikimedia Commons