The Rupel is a tidal river in northern Belgium, right tributary of the Scheldt. It is about 12 kilometres (7 mi) long. It flows through the Belgian province Antwerp. It is formed by the confluence of the rivers Dijle and Nete, in Rumst. It flows into the Scheldt at Rupelmonde. Towns along the Rupel are Rumst, Boom and Niel.