The Bolshoi Theatre (Russian: Большо́й теа́тр, tr. Bol'shoy Teatr, Big Theatre; IPA: [bɐlʲˈʂoj tʲɪˈatər]) is a historic theatre in Moscow, Russia, designed by architect Joseph Bové, which holds performances of ballet and opera. Before the revolution alongside with Maly Theatre (Small theatre) in Moscow and few theatres in Saint Petersburg (Hermitage Theatre, Bolshoi (Kamenny) Theatre, later Mariinsky Theatre and others) was a part of the Imperial Theatres of Russian Empire system.

The Bolshoi Ballet and Bolshoi Opera are amongst the oldest and most renowned ballet and opera companies in the world. It is by far the world's biggest ballet company, with more than 200 dancers. The theatre is the parent company of The Bolshoi Ballet Academy, a world-famous leading school of ballet. It has a branch at the Bolshoi Theatre School in Joinville, Brazil.

The main building of the theatre, rebuilt and renovated several times during its history, is a landmark of Moscow and Russia (its iconic neoclassical façade is depicted on the Russian 100-ruble banknote). On 28 October 2011, the Bolshoi re-opened after an extensive six-year renovation. The official cost of the renovation is 21 billion rubles ($688 million). However, other Russian authorities and other people connected to it claimed much more public money was spent. The renovation included restoring acoustics to the original quality (which had been lost during the Soviet Era), as well as restoring the original Imperial decor of the Bolshoi