The Thunder Bay Symphony Orchestra is a professional orchestra based in the Community Auditorium in Thunder Bay, Ontario, Canada. It was founded on 29 November 1960 as the Lakehead Symphony Orchestra, debuting at the Lakeview High School auditorium.

The TBSO is the largest fully professional arts group in Thunder Bay and the only professional orchestra between Toronto and Winnipeg. They have been a part of the cultural fabric of the city for 45 years.