American Ballet Theatre (ABT) is a classical ballet company based in New York City. Founded in 1939 by Lucia Chase and Richard Pleasant, it is recognized as one of the world's leading classical ballet companies. Through 2019, it had an annual eight-week season at the Metropolitan Opera House in the spring and a shorter season at the David H. Koch Theater in the fall; the company tours around the world the rest of the year. The company was scheduled to have a 5-week spring season at the MET preceded by a 2-week season at the Koch Theater beginning in 2020. ABT is the parent company of the American Ballet Theatre Jacqueline Kennedy Onassis School, and was recognized as "America's National Ballet Company" in 2006 by the United States Congress.

Lucia Hosmer Chase was an American dancer, actress, ballet director and also the co-founder of the American Ballet Theatre.