Frank Johnson (27 April 1855 – 25 April 1921) was mayor of Adelaide, South Australia from 1907 to 1909. He was born in Hindley Street, Adelaide, the son of Thomas Johnson, at one time member for West Adelaide and East Adelaide in the South Australian House of Assembly. He was educated at J. L. Young's Adelaide Educational Institution, joined his father's boot-making business in King William Street, then became a prominent auctioneer. He served as representative for the Gawler ward of the Adelaide City Council from 1891 to 1895, a post which his father had also once held.