O'Sullivan may refer to:
People O'Sullivan family, a gaelic Irish clan O'Sullivan (surname), a family name Sullivan (surname), a variation of the O'Sullivan family name
Places O'Sullivan Dam, Washington, United States O'Sullivan Army Heliport, California, United States O'Sullivan Beach, South Australia O'Sullivan Peak (Utah), United States O'Sullivan River, Quebec, Canada
Other uses O'Sullivan College, a private university in Canada O'Sullivan Ladies Open, an LPGA golf tournament O'Sullivan test, a diabetes screening test O'Sullivan v Noarlunga Meat Ltd, a series of Australian High Court cases
See also Sullivan (disambiguation)