The Oise (/wɑːz/ WAHZ; French: [waz] ⓘ) is a river of Belgium and France, flowing for 341 km (212 mi)[1] from its source in the Belgian province of Hainaut, south of Chimay.

It crosses the border with France after about 20 km (12 mi), and flows into the Seine at Conflans-Sainte-Honorine, a north-western suburb of Paris.

Robert Louis Stevenson described his canoeing trip on the Oise in his first published book, An Inland Voyage.

When the new Seine-Nord connection is complete, it will allow large vessels to transport goods from the Seine, and thus Paris and its surrounding area, to the ports of Dunkirk, Antwerp and Rotterdam.

Some bends need to be eased and bridges raised to meet the requirements of a class Vb inland waterway.