Tadao (written: 忠雄, 忠夫, 忠男, 忠生, 忠郎 or 理男) is a masculine Japanese given name. Notable people with the name include:
Tadao Ando (安藤 忠雄) (born 1941), Japanese architect
Aoyama Tadao (青山 忠雄) (1651–1685), Japanese daimyō
Tadao Baba (born 1944), Japanese motorcycle engineer
Tadao Chino (千野 忠男) (1934–2008), Japanese banker
Tadao Higuchi (樋口 忠男) (1916–1992), Japanese photographer
Tadao Horie (堀江 忠男) (1913–2003), Japanese footballer and manager
Tadao Ikeda (池田 忠雄) (1905–1964), Japanese screenwriter and film director
Tadao Kasami (嵩 忠雄) (1930–2007), Japanese information theorist
Tadao Kikumoto, Japanese inventor and engineer
Tadao Kobayashi (小林 忠生) (born 1930), Japanese footballer and manager
Tadao Mitome (三留 理男) (born 1938), Japanese photographer
Tadao Nagahama (長浜 忠夫) (1936–1980), Japanese anime director
Tadao Nakamura (born 1947), Japanese golfer
Tadao Oda (小田 忠雄) (born 1940), Japanese mathematician
Tadao Onishi (大西 忠生) (1943–2006), Japanese footballer
Tadao Sato (佐藤 忠男) (born 1930), Japanese film critic and theorist
Tadao Sawai (沢井 忠夫) (1938–1997), Japanese musician
Tadao Takayama (高山 忠雄) (1904–1980), Japanese footballer
Tadao Tannaka (淡中 忠郎) (1908–1986), Japanese mathematician
Tadao Tominari (冨成 忠夫) (1919–1992), Japanese photographer
Tadao Tomomatsu, American actor
Tadao Tosa (土佐 忠雄) (born 1942), Japanese diver
Tadao Uesako (上迫 忠夫) (1921–1986), Japanese gymnast
Tadao Umesao (梅棹 忠夫) (1920–2010), Japanese anthropologist
Tadao Watanabe (渡辺 忠雄), Japanese politician
Tadao Yanaihara (矢内原 忠雄) (1893–1961), Japanese economist and academic
Tadao Yasuda (安田 忠夫) (born 1963), Japanese sumo and professional wrestler
