Gentleman John, Gentleman Johnny, or Gentleman Jonathan may refer to:
Gentleman John: Johnny Enzmann (1890–1984), American Major League Baseball pitcher John Harris (footballer) (1917–1988), Scottish footballer John Jackson (English boxer) (1769–1845), English boxer John Palmer (actor) (1742?–1798), English actor John L. Rotz (1934–2021), American jockey John Sattler (born 1942), Australian rugby league footballer of the 1960s and 1970s
Gentleman Johnny: John Burgoyne (1722–1792), British Army general in the American Revolutionary War Johnny Ramensky (1905–1972), Scottish career criminal and Second World War British Army commando
Gentleman Jonathan "Gentleman" Jonathan Sayers, a professional wrestling manager from All- Star Wrestling
Fictional characters: "Gentleman" Johnny Marcone; see List of The Dresden Files characters