The Noyo River is a river on the north coast of California in Mendocino County. The river's headwaters are in the steep Mendocino Range, but downstream the river flows through gently sloping marine terraces before draining into the Pacific Ocean. The 113 square miles (290 km²) watershed extends east to the small city of Willits and the river's mouth is at Noyo Harbor in Fort Bragg, which uses the river for drinking water; it is neighbored on the south by the Big River, on the east by the South Fork Eel River, and on the north by Ten Mile River, named for its distance from the Noyo River. The average annual rainfall is between 40 inches (1,000 mm) and 65 inches (1,700 mm).

In the language of the Pomo people the Noyo River was called tee'mli-bida or Chemli-bida; the name "Noyo" referred to a village several miles north, on Pudding Creek, and by extension to the creek itself. The white settlers to the Fort Bragg area transferred the name from Pudding Creek to the larger river to the south.