The Dyle (French: [dil]; Dutch: Dijle [ˈdɛilə]) is a river in central Belgium, left tributary of the Rupel.

The most important cities along the Dyle are (starting from the source) Ottignies, Wavre, Leuven and Mechelen, the last of which is often called the 'Dijlestad' (Dyle City).

The main tributaries of the Dyle are the rivers Demer (in Werchter, Rotselaar municipality), and the Zenne at the Zennegat, on the farthest outskirts of Mechelen, where the canal Leuven-Mechelen also connects.

A few hundred metres downstream, the confluence of the Dyle and the Nete at Rumst forms the river Rupel, which 12 kilometres (7 mi) further comes into the Scheldt on which the Antwerp seaport is located.

From 1795 until 1815, when Belgium, the Netherlands and parts of Germany were incorporated into France, there was a department named after the river Dyle, see Dyle (department).