Frank Gaines Harris (April 25, 1871 – December 30, 1944) was an American Democratic politician from the state of Missouri.

He was the state's 33rd Lieutenant Governor and held that office longer than anyone else until Peter Kinder surpassed that record, serving three terms from 2005 until 2017.

[3][4] Harris established a law practice in Columbia, Missouri after passing the Bar.

Frank G. Harris served as Boone County Prosecuting Attorney for six years before being elected to the Missouri General Assembly.

[5] In 1932 he won the first of three consecutive terms as Lieutenant Governor and did not choose to run for a fourth.