Frank Henry Willard (1893-1958) was an American cartoonist and creator of the newspaper comic strip Moon Mullins.

Frank Willard was born in Anna, Illinois. Something of a hot-head, he was expelled from school as a youth and during his time in the army was reduced in rank three times from sergeant to private. He started his artistic career in 1914, working freelance for several Chicago newspapers, and in 1916 was hired by the Chicago Herald to work on the Sunday strip Tom, Dick and Harry. In 1920, after a short stint working with Billy DeBeck on Barney Google, he moved to King Features Syndicate, for whom he wrote and drew The Outta Luck Club. Captain Joe Patterson of the Chicago Tribune-New York News Syndicate was interested in adding a strip similar to Barney Google to his own lineup and hired Willard in 1923.

Moon Mullins ("Moon" being short for "Moonshine") debuted June 19, 1923 and quickly became a popular item. Supporting characters to the pugnacious Mullins included his landlady Emmy Schmaltz, Mamie the cook and her husband Willie, Moon's younger brother Kayo, and English peer Lord Plushbottom. At its peak the strip was carried by more than 250 newspapers; the strip and the character were so successful that it spawned a radio show, a game from Milton Bradley, two Big Little books, and in 1971 Moon Mullins appeared as a secondary character on the Saturday morning animated cartoon show Archie's TV Funnies.

Frank Willard was one of the first members of the National Cartoonists Society, joining within two weeks of its founding in 1932. Willard continued to work on Moon Mullins until his death in 1958, at which time it was taken over by his long-time assistant Ferd Johnson. Johnson continued the strip for another 68 years, until it finally ceased its run in 1991.