Judith Brenda Grinham, MBE (born 5 March 1939), also known by her married name Judith Rowley, is an English former competitive swimmer who represented Great Britain in the Olympics and European championships, and competed for England in the Commonwealth Games. Grinham is an Olympic gold medallist, Commonwealth and European champion, and former world record-holder. In 1959 she starred in the wartime comedy film Operation Bullshine as a PT Instructress.