The Muya River (Russian: Муя) is a 365 km long tributary of the Vitim in Buryatia, Russia.
The area through which the river flows is sparsely populated, the only settlement on the river being Taksimo, with the small village of Ust-Muya located where the river flows into the Vitim. The Muya is navigable for small craft from the Vitim around 70 km to Taksimo.
The Muya has lent its name to a number of other geographic features, including the Muysky Range, as well as the local government district Muysky Rayon.