Evinos (Greek: Εύηνος) is a 92-kilometre-long (57 mi) river in western Greece, flowing into the Gulf of Patras.

The river flows in a generally southwestern direction, for most of its length in Aetolia-Acarnania.

In its lower course it flows through lowlands, and it empties into the Gulf of Patras 10km southeast of Missolonghi.

Its area is about 5 to 10km², the height and the depth is approximately 50 m. It rarely supplies water to the area, but it is the westernmost and newest expansion of the water supply line Evinos-Mornos-Yliki-Marathon which covers the needs of Athens.

It is connected to the existing Mornos expansion via an underground pipeline 30km long and further to Athens.