Tethbae (pronounced [ˈteθve]; also spelled Tethba, often anglicised Teffia) was a confederation of túatha in central Ireland in the Middle Ages. It was divided into two distinct kingdoms, north Tethba, ruled by the Cenél Coirpri, and south Tethba, ruled by the Cenél Maini. It covered parts of County Westmeath and much of County Longford, counties which today are the far north-west part of the province of Leinster. In some cases Tethbae may refer to south Tethbae only.