Timaru Boys' High School, established in 1880, is a single sex state (public) secondary school located in the port city of Timaru, South Canterbury, New Zealand. TBHS caters for years 9 to 13.

Timaru is a port city in the southern Canterbury Region of New Zealand, located 157 km (98 mi) southwest of Christchurch and about 196 km (122 mi) northeast of Dunedin on the eastern Pacific coast of the South Island. The Timaru urban area is home to 28,900 people, and is the largest urban area in South Canterbury, and the third-largest in the Canterbury Region overall, after Christchurch and Rolleston. The town is the seat of the Timaru District, which includes the surrounding rural area and the towns of Geraldine, Pleasant Point and Temuka, which combined have a total population of 48,900.