The Haringvliet is a large (80 km²) inlet of the North Sea, in the province of South Holland in the Netherlands. It is an important estuary of the Rhine - Meuse delta.

Near Numansdorp, the Hollands Diep splits into the Haringvliet and the Volkerak estuaries. It is closed off near Goedereede from the North Sea by the Haringvlietsluices, which provide a road connection between the island of Voorne to the north, and the island of Goeree-Overflakkee to the south.

The sluices were built as part of the Delta Works sea barrier protection works, and allow for a brackish ecological environment.