Maria Callas (Greek: Μαρία Κάλλας) (New York City December 2, 1923 – Paris, France September 16, 1977) was an American-born Greek soprano and one of the most renowned opera singers of the twentieth century. She combined an impressive bel canto technique with great dramatic gifts. An extremely versatile singer, her repertoire ranged from classical opera seria to the bel canto operas of Donizetti, Bellini, and Rossini; further, to the works of Verdi and Puccini; and, in her early career, the music dramas of Wagner. Her remarkable musical and dramatic talents led to her being hailed as La Divina.

Born in New York City and raised by an overbearing mother, she received her musical education in Greece and established her career in Italy. Forced to deal with the exigencies of wartime poverty and with myopia that left her nearly blind on stage, she endured struggles and scandal over the course of her career. She turned herself from a heavy woman into a svelte and glamorous one after a mid-career weight loss, which might have contributed to her vocal decline and the premature end of her career. The press exulted in publicizing Callas's allegedly temperamental behavior, her supposed rivalry with Renata Tebaldi, and her love affair with Aristotle Onassis. Her dramatic life and personal tragedy have often overshadowed Callas the artist in the popular press. Her artistic achievements, however, were such that Leonard Bernstein called her "The Bible of opera", and her influence so enduring that, in 2006, Opera News wrote of her, "Nearly thirty years after her death, she's still the definition of the diva as artist—and still one of classical music's best-selling vocalists."

According to her birth certificate, Maria Callas was born Sophia Cecelia Kalos at Flower Hospital in Manhattan on December 2, 1923 to Greek parents George Kalogeropoulos and Evangelia "Litsa" (sometimes "Litza") Dimitriadou, though she was christened Maria Anna Sofia Cecilia Kalogeropoulou – the genitive of the patronymic Kalogeropoulos – (Greek: Μαρία Άννα Σοφία Καικιλία Καλογεροπούλου). Callas's father shortened the surname Kalogeropoulos first to "Kalos" and subsequently to "Callas" in order to make it more manageable.