Frank Michael Byrne (October 23, 1858 – December 24, 1927) was an American businessman and politician who served as the eighth Governor of South Dakota.

In 1885 and 1886, Byrne spent time in the northern part of Dakota Territory, investing in an insurance company in Fargo and then represented the firm in Faulk and Potter Counties in 1888.

In March 1913, Byrne became Governor of South Dakota after a hard-fought campaign against Judge James W. McCarter,[3] and went on to serve two terms from 1913 to 1917.

He left politics until 1922, when Governor William H. McMaster appointed him as Commissioner of Agriculture, a position he held until retiring in 1924.

A rheumatic condition forced Byrne to walk with a cane; and, he moved to the milder climates of Oregon and then California.