Lydia Boucher (28 February 1890 – 5 March 1971) was a Canadian composer, music educator, and nun.[1] She was active as a composer from 1923 to 1971, producing several choral works and pieces for solo piano and organ. Most of her works are sacred and many of them were published by L'Édition Belgo-Canadienne, Musica Enrégistré, and Éditions canadiennes. Her first composition was Ave Maria (1923) and her last work was Hommage à Mère Marie-Anne (1971). Of particular note is her oratorio L'Oeuvre d'Esther Blondin which premiered in 1949. Some of her other notable pieces include the piano works Trois Préludes (1928–30) and La Ronde des aiguilles (1950), and the Alleluia for organ (1958).[2]