Donald Trenner (March 10, 1927 – May 16, 2020) was an American jazz pianist and arranger born in New Haven, Connecticut.

He worked with Charlie Barnet in 1951 and following this with Jerry Gray, Charlie Parker, Stan Getz, Georgie Auld, Jerry Fielding, Skinnay Ennis, Les Brown, Dick Haymes, Jack Jones, Lena Horne, Ann-Margret, Shirley MacLaine and Nancy Wilson.

Additionally, he recorded with Tommy Dorsey, Vic Schoen, Howard McGhee, Frances Faye, Betty Roche, Nelson Riddle, Paul Broadnax, Charles Mingus, and Ben Webster.

In the 1960s, Trenner worked as a studio musician, and led The Steve Allen Show house band.

On April 22, 1947 in Elkton, Maryland, Trenner married singer Helen Carr, who sang with The Donn Trio.