Sōichi, Soichi or Souichi (written: 壮一, 宗一, 聡一, 奏一 or そういち in hiragana) is a masculine Japanese given name. Notable people with the name include:
Sōichi Aikawa (相川 宗一) (born 1942), Japanese politician
Soichi Fujita (藤田 宗一) (born 1972), Japanese baseball player
Soichi Ichida (1910–1986), Japanese philatelist
Sōichi Kakeya (掛谷 宗一) (1886–1947), Japanese mathematician
Souichi Moto (本 そういち), Japanese manga artist
Soichi Noguchi (野口 聡一) (born 1965), Japanese astronaut
Sōichi Ōya (大宅 壮一) (1900–1970), Japanese journalist
Soichi Tanaka (田中 奏一) (born 1989), Japanese footballer
Soichi Terada (寺田 創一) (born 1965), Japanese composer
