In music, '''Op. 12''' stands for Opus number 12. Compositions that are assigned this number include: * Adès – Arcadiana * Barber – Essay for Orchestra * Beethoven – Violin Sonata No. 1 * Beethoven – Violin Sonata No. 2 * Beethoven – Violin Sonata No. 3 * Braunfels – Prinzessin Brambilla * Dvořák – String Quartet No. 6 * Elgar – Salut d'Amour * Korngold – Die tote Stadt * Larsson – ''Little Serenade'' ({{lang|sv|Liten serenad}}), suite for strings (1934) * Luigini – Ballet égyptien * Mendelssohn – String Quartet No. 1 * Nielsen – Hymnus amoris * Pierné – Piano Concerto * Rachmaninoff – Caprice bohémien * Saint-Saëns – Oratorio de Noël * Schumann – Fantasiestücke, Op. 12 * Sibelius – Piano Sonata in F major (1893) * Vivaldi – Six Violin Concertos, Op. 12 * Ysaÿe – Poème élégiaque in D minor, Op.12 {{Opus number disambiguation|Op=012}}