The St Lythans burial chamber is a single stone megalithic dolmen, built around 4,000 BC as part of a chambered long barrow, during the mid Neolithic period, in what is now known as the Vale of Glamorgan, Wales.

St Lythans is an affluent hamlet and former parish in the Vale of Glamorgan, southeast Wales, just outside western Cardiff. It lies southwest of Culverhouse Cross, west of Wenvoe and southwest of Twyn-yr-Odyn and is also connected by road from Dyffryn and the Five Mile Lane in the west. It is one of the wealthiest communities in the Vale of Glamorgan, containing some notable mansions and cottages, valued on average at over £500,000 as of 2011. The megalithic St Lythans burial chamber, over 6000 years old, lies 1 km to the west of the village and the hamlet also contains the St.Lythans Parish Church or Church of St Bleddian, a Grade II* listed building.