Sean Kenniff (born 27 November 1969) is an American physician who appeared on the first series of the television show Survivor (later called Survivor: Pulau Tiga), filmed and broadcast in 2000.

He was the twelfth of fifteen contestants to be eliminated, and was famous for his "Alphabet Voting" strategy, in which he cast his votes based on the order of contestants' names in the alphabet.[1] Sean was a Tagi, and his system conveniently targeted players from the Pagong tribe first.

Kenniff was born in Massapequa, New York; his father was a firefighter. He graduated from Massapequa High School and received a Bachelor of Science degree in biology at the State University of New York at Binghamton in 1991. He received an M.D. at New York Medical College in 1995, and did a three year residency followed by a year as Chief Resident in neurology at Long Island Jewish Medical Center , which is affiliated with Albert Einstein College of Medicine.

He has said that he wants to be a writer; after appearing on Survivor he made acting appearances on The Guiding Light and appeared as a medical correspondent on various news programs.