Kazumasa (written: 数正, 和正, 和昌, 和政, 一眞, 一正, 一将, 一存, 一政 or 員昌) is a masculine Japanese given name. Notable people with the name include:
Kazumasa Azuma (東 和政) (born 1982), Japanese baseball player
Kazumasa Hashimoto (橋本 和昌) (born 1974), Japanese musician
Kazumasa Hirai (author) (平井 和正) (born 1938), Japanese writer
Kazumasa Hirai (weightlifter) (平井 一正) (born 1949), Japanese weightlifter
Ikoma Kazumasa (生駒 一正) (1555–1610), Japanese samurai
Ishikawa Kazumasa (石川 数正) (1534–1609), Japanese samurai
Isono Kazumasa (磯野 員昌) (1534–1583), Japanese samurai
Kazumasa Kawano (河野 和正) (born 1970), Japanese footballer
Kazumasa Oda (小田 和正) (born 1947), Japanese singer-songwriter and composer
Ogawa Kazumasa (小川 一眞) (1860–1929), Japanese photographer
Kazumasa Sakai (坂井 一将) (born 1990), Japanese badminton player
Kazumasa Sasaki (佐々木 一正) (born 1989), Japanese ice hockey player
Seki Kazumasa (関 一政) (1564–1625), Japanese daimyō
Kazumasa Shimizu (born 1976), Japanese footballer
Sogō Kazumasa (十河 一存) (1532–1561), Japanese samurai
Kazumasa Takagi (高木 和正) (born 1984), Japanese footballer
Kazumasa Tsujimoto (辻本 和正) (born 1975), Japanese boxer
Kazumasa Uesato (上里 一将) (born 1986), Japanese footballer
