Paul Alexander Casey (born 21 July 1977) is an English golfer who is a member of the world's top two professional golf tours, the U.S.-based PGA Tour and the European Tour. In 2009 he achieved his highest position, third, in the Official World Golf Rankings. .

Casey was born in Cheltenham, but moved with his family to Weybridge, Surrey at the age of six. After attending Cleves School, Weybridge and then Hampton School, he studied A levels at Strode's College, Egham. He then took a golf scholarship at Arizona State University.

His amateur career was distinguished. In the U.S. he was the first man to win three consecutive Pac-10 Championships (1998, 1999 and 2000). In 2000 he broke the championship scoring record held by Tiger Woods (18 under par) with a 23 under par 265. Back on the other side of the Atlantic he won the English Amateur in 1999 and 2000. He was also a member of Great Britain and Ireland’s winning 1999 Walker Cup team, where he was only the third player in seventy seven years to record four victories without a single defeat.