Isao (いさお, イサオ) is a masculine Japanese given name which was popular during the Shōwa period.
Isao can be written using different kanji characters and can mean:
功, "achievement"勲, "meritorious"績, "exploits"公, "public"勇夫, "brave, man"勇雄, "brave, masculine"伊佐夫伊佐雄伊三男The name can also be written in hiragana or katakana.
Isao Aoki (功, born 1942), Japanese professional golferIsao Harimoto (勲, born 1940), Zainichi Korean professional baseball playerIsao Hashizume (功, born 1941), Japanese actorIsao Homma (born 1981), Japanese footballer who plays for Albirex NiigataIsao Inokuma (功, 1938–2001), Japanese judokaIsao Iwabuchi (born 1933), Japanese Olympic football playerIsao Kikuchi (born 1921), American graphic designer, painter, carver, illustratorIsao Kimura (功, 1923–1981), Japanese actorIsao Kubota (born 1983), Japanese footballer who plays for Samut SongkhramIsao Matsuoka (功, born 1934), Chairman of TohoIsao Morishita, Japanese Grand Prix motorcycle road racerIsao Nakauchi (功, 1922–2005), founder of DaieiIsao Obata (1904–1976), pioneering Japanese master of Shotokan karateIsao Okano (功, born 1944), Japanese judokaIsao Okawa (功, 1926–2001), former Chairman of SegaIsao Okazaki (功, 1920–2006), a Japanese right-wing activistIsao Sasaki, (功）, a Japanese anime singer, actor, and voice actorIsao Shinohara, (篠原 功）, a Japanese voice actorIsao Takagi (功, born 1961), Japanese professional wrestlerIsao Takahata (勲, born 1935), Japanese anime directorIsao Tamagawa (伊佐男, 1922–2004), Japanese actorIsao Tomita (勲, born 1932), Japanese electronic music composerIsao Yamagata (1915–1996), Japanese film actor (fl. 1951 and 1984)Isao Yoneda (功, born 1977), Japanese gymnastIsao Yukisada (勲, born 1968), Japanese film directorIsao Iinuma, the protagonist of the 1969 novel Runaway Horses by Yukio MishimaIsao Ohta (功), a character in the anime and manga series Mobile Police Patlabor