Biff Howard Tannen is a fictional character and a major antagonist in the Back to the Future trilogy. Thomas F. Wilson plays Biff in all three films as well as the Universal Studios ride, and voiced the character in the animated series. Aidan Cutler played him in the original West End production of the first film's stage musical adaptation, and Nathaniel Hackmann plays him in the Broadway production. Biff is the main antagonist of the first and second films. Biff's great-grandfather, Buford "Mad Dog" Tannen, is the main antagonist of the third.

Back to the Future is an American science fiction comedy franchise created by Robert Zemeckis and Bob Gale. The franchise follows the adventures of a high school student, Marty McFly, and an eccentric scientist, Dr. Emmett "Doc" Brown, as they use a DeLorean time machine to time travel to different periods in the history of the fictional town of Hill Valley, California.