Lev Ivanovich Ivanov was a Russian ballet dancer and choreographer and later, Second Balletmaster of the Imperial Ballet. As a performer with the Imperial Ballet, he achieved prominence after performing as an understudy in a benefit performance of La Fille Mal Gardée. He is most famous as the choreographer of Acts II and IV of Swan Lake, which include the Dance of the Little Swans, Act II of Cinderella, and The Nutcracker, which he choreographed alongside Marius Petipa.

A ballet master is an employee of a ballet company who is responsible for the level of competence of the dancers in their company. In modern times, ballet masters are generally charged with teaching the daily company ballet class and rehearsing the dancers for both new and established ballets in the company's repertoire. The artistic director of a ballet company, whether a male or female, may also be called its ballet master. Historic use of gender marking in job titles in ballet is being supplanted by gender-neutral language job titles regardless of an employee's gender.