Sir Trevor Williams, 1st Baronet (c. 1623 – 1692) of Llangibby (Welsh: Llangybi), Monmouthshire, was a Welsh gentry landowner and politician who sat in the House of Commons at various times between 1660 and 1692. He played a significant part in events during and after the English Civil War in South Wales, siding first with King Charles, then with the Parliamentarians, before rejoining the Royalists in 1648.