The Spui is a small tidal river in South Holland in the Netherlands. Historically, it forks off the Oude Maas river at the town of Oud-Beijerland to end in the Haringvliet estuary, but as a (planned) result from the Delta Works, its flow has actually been reversed.

There are no bridges or tunnels crossing the Spui, but there is a car ferry from Voorne-Putten island on the north near Spijkenisse to Hoekse Waard island on the south near Nieuw-Beijerland.