Richard Francis Hayes (1882 – 16 June 1958) was an Irish politician, historian and medical doctor. He was a volunteer and fought in the Easter Rising in 1916 and was involved in the Garristown and Ashbourne fighting. For several years he was the closest friend of Frank O'Connor, who acknowledged the extraordinary help Hayes gave him in researching The Big Fellow, his biography of Michael Collins. After some years, however, the friendship cooled, and the portrait of Hayes in O'Connor's memoir My Father's Son, is surprisingly unflattering, given their earlier closeness.