Tosu or tOSU may refer to:
Cities
- Tosu, Russia, a selo (village) in Vilyuysky District, Sakha Republic
- Tosu, Saga, a city in Japan
- Sagan Tosu, an association football club in Tosu, Saga
- Shin-Tosu Station, a railway station in Tosu, Saga
- Tosu Futures, a former football club in Tosu, Saga
- Tosu Stadium, a football stadium in Tosu, Saga
- Tosu Station, a railway station in Tosu, Saga
- Tosu language, in the Qiangic and Tibeto-Burman language groups
- Toșu, a Romanian surname
Universities
- Ohio State University, from a marketing tactic used by the university to refer to it as "The Ohio State University".