, other romanizations include Ōnishi, Oonishi, and Ohnishi with long vowel ō, is a Japanese surname or a Japanese place name. with short vowel o, is a Japanese surname. with short vowel o, is a Japanese place name.

It may refer to:

With long vowel ō People Aijiro Onishi (大西 愛治郎, 1881–1958), Japanese religious leader Hiroshi Ōnishi (大西 博, 1961–2011), Japanese painter and University professor Junko Onishi (musician) (大西 順子, born 1967), Japanese post-bop jazz pianist Junko Onishi (swimmer) (大西 順子, born 1974), swimmer from Japan, won a bronze medal at the 2000 Summer Olympics Koji Onishi (大西 孝治, born 1988), Japanese footballer Kazumi Onishi (大西 一美, born 1948), Japanese figure skater Masayuki Onishi (大西 昌之, born 1977) Japanese football player Mitsugu Ōnishi (大西みつぐ, born 1952), Japanese photographer Nanami Onishi| (大西七海), Japanese skateboarder Norimitsu Onishi (大西 哲光), Canadian journalist Tadao Onishi (大西 忠生, 1943–2006) Japanese football player Takashi Onishi (大西 貴, born 1971), Japanese football player Takijirō Ōnishi (大西 瀧治郎, 1891–1945), admiral in the Imperial Japanese Navy, known as the father of the kamikaze Takuya Onishi (大西 卓哉, born 1975), Japanese astronaut Tama Onishi (大西 玉, 1916–1969), Japanese religious leader Onishi Tetsunosuke (大西鐡之祐) 1916–1995), professor and coach of the Japan national rugby union team Yohei Onishi (大西 容平, born 1982), Japanese football player Yoshiaki Onishi (大西 義明, born 1981) composer, conductor, and clarinetist , Japanese rower Yuka Onishi (大西結花, born 1968) Japanese actress and idol singer, known for her role in the TV series Sukeban Deka III , Japanese footballer Yuki Onishi (chef) Ai Haruna (born 1972 as Kenji Ōnishi (大西 賢示)), Japanese transsexual TV personality and singer

Places Ōnishi, Ehime (大西町), Japan Ōnishi Station (大西駅), a railway station in Imabari, Japan

Other uses 9062 Ohnishi, asteroid

With short vowel o People

Places Onishi, Gunma (鬼石町), Japan