The Sergeyev Collection (officially Nikolai Sergeev Dance Notations and Music Scores for Ballets) is an assemblage of materials that document the repertory of the Imperial Ballet of St. Petersburg as it existed at the turn-of-the 20th century. The collection consists primarily of choreographic notation and music for many of the notated works. Also included are designs for stage décor and costumes, photos, and theatre programmes for performances of the Imperial Ballet at the turn-of-the 20th century. The choreographic notations of the Sergeyev Collection record—in varying degrees of detail—the original works and revivals of the choreographer Marius Petipa, who served as Premier Maître de ballet of the St. Petersburg Imperial Theatres from 1871 until 1903. Also included is notation for choreography by Lev Ivanov, who served as Second Maître de ballet of the St. Petersburg Imperial Theatres from 1885 until his death in 1901. The dance sections of several operas are also among the notated choreographies of the Sergeyev Collection, the majority of which are the work of Petipa and Ivanov, respectively.
The collection is named for Nicholas Sergeyev, former dancer and régisseur-général of the St. Petersburg Imperial Theatres, who brought the collection out of Russia after the Russian Revolution of 1917. Since 1969 these materials have been held in the Harvard Theatre Collection at Houghton Library.