Masuo (written: 益男, 斗雄 or 満寿夫) is a masculine Japanese given name. Notable people with the name include:
(born 1958), Japanese actor and voice actor (born 1947), Japanese sumo wrestler (1934–1997), Japanese artist, writer and film director
Masuo (written: 増尾) is also a Japanese surname. Notable people with the surname include: (born 1986), Japanese actor
See also Masuo Station (disambiguation), multiple train stations in Japan