Sadao (written: , , or in katakana) is a masculine Japanese given name. Notable people with the name include:
, Japanese actor and musician , Imperial Japanese Army general, politician, and political philosopher , Japanese classical composer , Japanese politician , Japanese gay erotic artist , Japanese sport wrestler , Japanese sumo wrestler , United States Army soldier and Medal of Honor recipient , Japanese film director and screenwriter , Japanese sport wrestler , Japanese astronomer , Japanese entomologist , Japanese sumo wrestler , Japanese printmaker , Japanese jazz musician , Japanese politician , Japanese film director and screenwriter