The Mariinsky Theatre is a historic theatre of opera and ballet in Saint Petersburg, Russia. Opened in 1860, it became the preeminent music theatre of late 19th century Russia. Today, the Mariinsky Theatre is home to the Mariinsky Ballet, Mariinsky Opera and Mariinsky Orchestra.

The repertoire of Mariinsky aims to demonstrate the supreme art of the performers in its companies and its stage, linking the history of the Theatre with contemporary audiences and with contemporary works from the diverse genres of opera, ballet and symphonic music.

A new building has been recently added to the original one, with the latest technology in its main stage and three new chamber venues. The building covers 79,114 m2, and it is one of the largest theatre and concert venues in the world. The auditorium seats up to 2,000 people at full capacity.

In 2009, Mariinsky launched its own record label.