Ōishi (surname)
Ōishi, Oishi or Ooishi is a Japanese surname. Notable people with the surname include:
- Daijiro Oishi, Japanese baseball player
- Hisako Ōishi, Japanese politician of the Democratic Party of Japan
- Makoto Oishi, Japanese wrestler, currently working for Kaientai Dojo
- Masamitsu Oishi, Japanese politician of the Democratic Party of Japan
- Nobuyuki Oishi, former Japanese football player
- Ryuhei Oishi, Japanese footballer
- Sadahisa Ōishi, retainer of the Ogigayatsu-Uesugi branch of the Uesugi, and the builder of Takiyama Castle
- Tadashi Ōishi, Japanese shogi player
- Takaya Oishi, former Japanese football player
- Tamotsu Oishi, career officer in the Imperial Japanese Navy during World War II
- Tsugutoshi Oishi, Japanese footballer
- Yasuko Oishi, Japanese swimmer
- Yoshino Ōishi, Japanese photographer
- Yoshio Ōishi, the chamberlain of the Akō han in Harima Province, Japan, known as the leader of the Forty-seven rōnin.