Valentin or Valentín is a surname. Notable people with the surname include:
Barbara Valentin (1940–2002), Austrian actress Dave Valentin (1952–2017), American Latin jazz flautist Isabelle Valentin (born 1962), French politician Javier Valentín (born 1975), Puerto Rican baseball player Jesmuel Valentín (born 1994), Puerto Rican baseball player José Valentín (born 1969), Puerto Rican baseball player Katy Valentin (1902-1970), Danish stage and film actress Lydia Valentín (born 1985), Spanish Olympic weightlifter Rodolfo Valentin (born 1944), Argentine hairdresser