Alexander Mackenzie (1847-1935): Colomba, His Majesty

James MacMillan (1959- ): Inés de Castro

Elizabeth Maconchy (1907-1994): The Departure, The Sofa, The Three Strangers

Bruno Maderna (1920-1973): Satyricon

Albéric Magnard (1865-1914): Guercoeur

Gian Francesco Malipiero (1882-1973): Torneo notturno

Philippe Manoury (1952- ): 60th Parallel, K

Marin Marais (1656-1728): Alcyone, Semele

Filippo Marchetti (1831-1902): Romeo e Giulietta, Ruy Blas

Heinrich Marschner (1795-1861): Hans Heiling, Der Templer und die Jüdin, Der Vampyr

Bohuslav Martinů (1890-1958): Alexander Twice (Alexandre bis), Ariane, Comedy on the Bridge (Veselohra na mostě), The Greek Passion (Řecké pašije), Julietta, Mirandolina, The Marriage (Ženitba), The Plays of Mary (Hry o Marii), Les trois souhaits, The Voice of the Forest (Hlas lesa), What Men Live By (Čím člověk žije)

Pietro Mascagni (1863-1945): L'amico Fritz, Cavalleria rusticana, Iris, Isabeau, Le maschere, Nerone, Parisina, Il piccolo Marat

Benedict Mason (1954- ): Playing Away

Victor Massé (1822-1884): Les noces de Jeannette

Jules Massenet (1842-1912): La grand'tante , Don César de Bazan, Le roi de Lahore, Hérodiade, Manon, Le Cid , Esclarmonde, Le mage, Werther, Thaïs, Le portrait de Manon, La Navarraise, Sapho, Cendrillon, Grisélidis, Le jongleur de Notre-Dame, Chérubin, Ariane, Thérèse, Bacchus, Don Quichotte, Roma, Panurge, Cléopâtre, Amadis

Teizo Matsumura (1929- ): Chinmoku (The Silence)

Nicholas Maw (1935- ): The Rising of the Moon, Sophie's Choice

Toshiro Mayuzumi (1929-1997): Kinkakuji (The Golden Pavilion)

Simon Mayr (1763-1845): L'amor coniugale, Ginevra di Scozia, La Lodoiska, Medea in Corinto, La rosa bianca e la rosa rossa

Domenico Mazzocchi (1592-1665): La catena d'Adone

Virgilio Mazzocchi (1597-1646): Chi soffre, speri (with Marco Marazzoli)

Richard Meale (1932- ): Voss

Kirke Mechem (1925- ): Tartuffe

Etienne Méhul (1763-1817): Ariodant, Le jeune Henri, Joseph, Mélidore et Phrosine, Stratonice, Uthal

Gian-Carlo Menotti (1911-2007): Amahl and the Night Visitors, Amelia Goes to the Ball, The Boy Who Grew Too Fast, The Consul, Help, Help, the Globolinks!, The Last Savage, Maria Golovin, The Medium, The Old Maid and the Thief, The Saint of Bleeker Street, The Telephone, or L'Amour à trois

Saverio Mercadante (1795-1870): Il bravo, I due Figaro, Elena da Feltre, Emma d'Antiochia, Il giuramento, Orazi e Curiazi, Pelagio, Il regente, La vestale, Virginia

André Messager (1853-1929): Monsieur Beaucaire, Les p'tites Michu, Mirette,

Olivier Messiaen (1908-1992): Saint François d'Assise

Giacomo Meyerbeer (1791-1864): L'Africaine, Il crociato in Egitto, L'esule di Granata, L'étoile du nord, Ein Feldlager in Schlesien, Les Huguenots, Margherita d’Anjou, Le prophète, Robert le diable

Minoru Miki (1930- ): Ada, An Actor's Revenge, Genji monogatari, Jōruri, Shunkinshō

Darius Milhaud (1892-1974): L'abandon d'Ariane, Bolivar, Christophe Colomb, David, La mère coupable, Le pauvre matelot

Karl Millöcker (1842-1899): Der arme Jonathan, Der Bettelstudent, Die Dubarry, Gasparone, Das verwunschene Schloss

Richard Mills (1949-): Summer of the Seventeenth Doll, Batavia, The Love of the Nightingale

Jean-Joseph de Mondonville (1711-1772) Les fêtes de Paphos, Titon et l'Aurore

Stanisław Moniuszko (1819-1872): Biuraliści, Halka, The Haunted Manor (Straszny dwór), The New Don Quixote, or 100 Follies, A Night in the Appenines

Pierre-Alexandre Monsigny (1729-1817) Le déserteur

Michel Pignolet de Montéclair (1667-1737): Les festes de l'été, Jephté

Italo Montemezzi (1875-1952): L'amore dei tre re, Giovanni Galurese, Hellera, L'incantesimo, La nave, La notte di Zoraima

José Ángel Montero (1832-1881): Virginia

Claudio Monteverdi (1567-1643): L'incoronazione di Poppea, Orfeo, Il ritorno d'Ulisse in patria

Douglas Stuart Moore (1893-1969): The Ballad of Baby Doe, The Devil and Daniel Webster

Wolfgang Amadeus Mozart (1756-1791): Apollo et Hyacinthus, Ascanio in Alba, Bastien und Bastienne, La clemenza di Tito, Così fan tutte, Don Giovanni, Die Entführung aus dem Serail, La finta giardiniera, La finta semplice, Idomeneo, Lucio Silla, The Magic Flute, The Marriage of Figaro, Mitridate, re di Ponto, L'oca del Cairo, Il re pastore, Der Schauspieldirektor, Die Schuldigkeit des ersten Gebotes, Il sogno di Scipione, Lo sposo deluso, Thamos, König in Ägypten, Zaide

Thea Musgrave (1928- ): A Christmas Carol, The Decision, Harriet, the Woman called 'Moses', Mary, Queen of Scots, An Occurrence at Owl Creek Bridge, The Voice of Ariadne

Modest Mussorgsky (1839-1881): Boris Godunov, The Fair at Sorochintsï (Sorochinskaya Yarmarka), Khovanshchina, Zhenitba (The Marriage), Salammbô

Josef Mysliveček (1737-1781): Il Bellerofonte