Frank Bartlett Willis (December 28, 1871 - March 30, 1928) was a Republican politician from Ohio. He served as the 47th Governor of Ohio.

Willis was born in Lewis Center, Ohio and graduated from Ohio Northern University in 1894. After teaching at Ohio Northern for twelve years, Willis was admitted to the bar and began practicing law. He served in the Ohio House of Representatives from 1900-1904 while teaching at Ohio Northern, and was subsequently elected to the U.S. House of Representatives in 1910, serving from 1911-1915. He was elected to the governorship in 1914 and served one two-year term from 1915-1917, and was not re-elected. He was elected to the U.S. Senate in 1920, replacing Warren Harding. Harding then resigned his seat to take the presidency, allowing Willis to take his seat early. Willis died in office in 1928.