Mantarō, Mantaro or Mantarou (written: 萬太郎 or 万太郎) is a masculine Japanese given name. Notable people with the name include:
(1932–1987), Japanese linguist and sinologist (1889–1963), Japanese writer, playwright and poet
Fictional characters: , protagonist of the manga series Kinnikuman Nisei Big Man of Deep Cut, an idol group from Splatoon