Dominique Lorraine Diezi (born 14 July 1977) is a Swiss former swimmer who specialized in sprint freestyle events. She is a two-time Olympian (1996 and 2004), a 32-time Swiss national champion, a multiple-time record holder in sprint freestyle (50 and 100 m), and a member of Switzerland's national swimming team (1992–2004). She also earned multiple All-American honors while studying in the United States. In 2011, Diezi was named women's assistant coach for the Yale Bulldogs swimming and diving team at Yale University.