James William Dietz (born January 12, 1949) is an American rower and rowing coach. Dietz was born in 1949 in The Bronx. He obtained his education at Northeastern University, from where he graduated in 1972. He competed at the 1972 Summer Olympics in Munich in the single sculls and came fifth. He went to the 1976 Summer Olympics in Montreal and came seventh in the single sculls. He made the team for the 1980 Summer Olympics but did not travel to Moscow due to the boycott initiated by the United States.