Mary Beth Dunnichay (born February 25, 1993 in Elwood, Indiana) is an American platform diver. Her older brother Caleb is also a competitive diver for Auburn University.
She has been named to the 2008 U.S. Olympic team in both the 10-meter platform and the synchronized 10-meter platform event with Haley Ishimatsu. In the synchronized competition Ishimatsu and Dunnichay earned fifth place scoring 309.12.