Frank Otis Frost (April 15, 1936 or 1938 – October 12, 1999) was one of the foremost American Delta blues harmonica players of his generation.

Most sources state that Frost was born in 1936 in Auvergne, Jackson County, Arkansas, though researchers Bob Eagle and Eric LeBlanc state Patterson, Woodruff County, in 1938. Frost began his musical career at a young age by playing the piano for his family church. At the age of 15, Frost left for St. Louis, where he became a guitarist. At the age of 18, Frost began touring with drummer Sam Carr and Carr’s father, Robert Nighthawk. Soon after touring, he toured again with Sonny Boy Williamson II for several years, who helped teach him how to play the harmonica.