Ōigawa or Oigawa ( or 大堰川, "Ōi River") is a Japanese family name and a toponym. It may refer to:
Kazuhiko Ōigawa, a Japanese politician and the current governor of Ibaraki Prefecture Ōigawa, Shizuoka, a former town in Shizuoka Prefecture, Japan Ōigawa Railway, a railway company in Shizuoka Prefecture, Japan Ōigawa Main Line, a Japanese railway line which connects Kanaya Station in Shimada with Senzu Station in Kawanehon (both in Shizuoka Prefecture) Ōi River (in Japanese: Ōi-gawa), a river in Shizuoka Prefecture, Japan Ōigawa Dam, a dam on the Ōi River
See also Oikawa