The River Yox is a river in the English county of Suffolk. It flows from the west of Peasenhall through Sibton and Yoxford where it becomes the Minsmere River. The Yox was originally fordable at Yoxford where a modern road bridge allows the A12 to cross the river.
The river valley is largely drained and used as grassland with some arable use at Sibton. Some peat deposits are present. The valley has a narrow floodplain with water meadows and has largely been drained using a system of dykes.
Coordinates: 52°15′53″N 1°31′14″E / 52.2646°N 1.5206°E / 52.2646; 1.5206