Sir James Arthur Ratcliffe (born 18 October 1952) is a British billionaire, chemical engineer, and businessman. Ratcliffe is the chairman and chief executive officer (CEO) of the INEOS chemicals group, which he founded in 1998.

In May 2018, Ratcliffe was the richest person in the UK, with a net worth of £21.05 billion. As of May 2023, the Sunday Times Rich List 2023 estimated his net worth at