Op. 21

In music, Op. 21 stands for Opus number 21. Compositions that are assigned this number include:

• Barber – Capricorn Concerto
• Beethoven – Symphony No. 1
• Britten – Diversions for Piano Left Hand and Orchestra
• Chopin – Piano Concerto No. 2
• Dvořák – Piano Trio No. 1
• Enescu – Symphony No. 3
• Giraud – Pierrot lunaire
• Graham – Episodes
• Lalo – Symphonie espagnole
• Larionov – Chout
• Oswald – Cello Sonata No. 1
• Ries – Cello Sonata No. 3
• Sarasate – Spanish Dances, Book I
• Schumann – Novelletten
• Sibelius – "Hymn", song for male choir a cappella (1896, revised 1898)
• Villiers – Elegiac Ode
• Weill – Der Zar lässt sich photographieren