The Muisne River is a river of Ecuador that enters the Pacific Ocean in the Esmeraldas Province.

The Muisne River is the main river in Cojimíes sub-region of the Manabí mangroves ecoregion. It discharges 22 cubic metres per second (780 cu ft/s) into the Pacific. The low-keyed Muisne resort is in the northern part of the Ensenada de Mompiche, on a 7 kilometres (4.3 mi) sand bar among the mangroves of the Muisne River estuary. It may be reached by ferry across the Muisne River from the small town of El Relleno.

• List of rivers of Ecuador