Coordinates: 52°34′16″N 3°02′20″W / 52.571°N 3.039°W The River Onny is a river in Shropshire, England. It is a major tributary of the River Teme.
The river has its sources in the Shropshire Hills at White Grit, located in Mid and South-west Shropshire. It has two branches, the East Onny and West Onny, which converge at Eaton, to the east of Lydham. The River Onny then flows in a South-easterly direction, through Craven Arms and Onibury, before it finally has its confluence with the River Teme just upstream of Ludlow at Bromfield. The River Teme is itself a tributary of the River Severn, confluencing just south of Worcester city centre. The River Severn then flows south-west meeting the sea at Bristol. The Onny has the type section just west of Craven Arms of the Caradocian series of the Ordovician system and there is a trilobite genus Onnia.