| Country | Ireland |
|---|---|
| Ancestral house | Laigin |
| Titles | |
| Founder | Énnae Cennsalach |
| Current head | William Butler MacMurrough Kavanagh (born 1944) |
| Founding | 5th century |
| Cadet branches | O'Morchoe |
The Uí Ceinnselaig (also Uí Cheinnselaig, anglicised as Kinsella), from the Old Irish "grandsons of Cennsalach", are an Irish dynasty of Leinster who trace their descent from Énnae Cennsalach, a supposed contemporary of Niall of the Nine Hostages. Énda was said to be a grandson of Bressal Bélach and a first cousin of Dúnlaing mac Énda Niada, eponymous ancestor of the rival Uí Dúnlainge.
The earliest associations of the Uí Ceinnselaig are with the region around Rathvilly, County Carlow, and the headwaters of the River Slaney, but in time the centre of their power was pushed southwards, later being found around Ferns, in County Wexford, site of the monastery of Saint Máedóc (d. 626 or 632).
In early times the Kings of Leinster came from the Uí Ceinnselaig and the Uí Dúnlainge, but the Uí Dúnlainge came to dominate the kingship of the province, and after Áed mac Colggen (d. 738) it was three hundred years until the next Uí Ceinnselaig king of Leinster, Diarmait mac Mail na mBo. See Kings of Uí Ceinnselaig.
Notable kings of the Uí Ceinnselaig and related kindreds included: