Syndicated newspaper comic strip by Bud Fisher (Harry Conway Fisher) that began in 1907 under the title A. Mutt. The title character was a henpecked husband who was overfond of drinking and gambling on the horses. Mutt was tall, lean, and slow-witted; the strip really took off in popularity when he paired up with a short, round, insane character named Jeff. After a while Fisher stopped drawing the strip himself, supervising a staff of illustrators who did the work for him. The most prominent of these was Al Smith, who worked on the strip from 1932 to 1980. It ended in 1982. Some claim that Mutt & Jeff was the first daily comic strip ever, but others believe that to have been A. Piker Clerk which started in 1904.

As a slang term, "Mutt and Jeff" refers to any pairing of a tall and a short man, though it could mean two men of widely dissimilar characteristics.