The Yom River (Thai: แม่น้ำยม, RTGS: Maenam Yom, pronounced [mɛ̂ː.náːm jōm]; Northern Thai: น้ำแม่ยม, pronounced [náːm mɛ̂ː.ɲōm]) is a river in Thailand.

The Yom River has its source in the Phi Pan Nam Range in Pong District, Phayao Province.

The Yom river and its tributaries drain a total area of 24,047 square kilometres (9,285 sq mi) of land (called the Yom Basin) in the provinces of Sukhothai, Phitsanulok, Phichit, Phrae, and Lampang.

A controversial large dam was planned on the Yom River in the central area of the Phi Pan Nam mountains in Kaeng Suea Ten in 1991 but the project was later abandoned.

[4] Currently a proposal is being debated to build two smaller dams on the Yom River in the area instead of the Kaeng Suea Ten mega-dam.