Ester Mägi (born 10 January 1922) is an Estonian composer, widely regarded as the First Lady of Estonian Music.
Her compositional output is substantial and represents all genres, from chamber and vocal music to choral and highly regarded symphonic works. She trained initially under Mart Saar at the Tallinn Conservatory, then from 1951 to 1954 at the Moscow Conservatory under Vissarion Shebalin. Amongst her best-known works are her Piano Sonata (1949), Piano Trio in F minor (1950), Piano Concerto (1953), Violin Concerto (1958), Symphony (1968), Variations for Piano, Clarinet and Chamber Orchestra (1972), Bukoolika for orchestra (1983) and Vesper for violin and piano/organ (1990, arranged for strings in 1998). Much of her work has been inspired by Estonian folk music.