The Trondheim Symphony Orchestra (Norwegian: Trondheim Symfoniorkester) is a Norwegian orchestra based in Trondheim, Norway. Its principal concert venue is the Olavshallen. The orchestra is organised as a trust and receives public assistance from the Norwegian government, Sør-Trøndelag county and the municipality of Trondheim.
The precursor ensemble of the Trondheim Symphony Orchestra held its first concert 10 December 1909, at the Frimurerlogen ('Masonic Lodge') in Trondheim, with an ensemble of 29 players. Through the 1920s, the orchestra's musical activities were modest, but this changed in the 1930s, with an increase in the availability of better-trained musicians and increased financial subsidies, to allow for increased (though not abundant) pay to the orchestra musicians. During World War II, the Frimurerlogen was renamed the Deutsches Haus, whilst the country was under German occupation, and the orchestra gave concerts in various Trondheim churches. Following World War II, the orchestra returned to the Frimurerlogen as its resident venue and remained there until 1989.