In music, Op. 81 stands for Opus number 81. Compositions that are assigned this number include:
Beethoven – Piano Sonata No. 26 Beethoven – Sextet for Horns and String Quartet Brahms – Tragic Overture Dvořák – Piano Quintet No. 2 Elgar – The Sanguine Fan Milhaud – La création du monde Prokofiev – Semyon Kotko Sallinen – Symphony No. 8 Schumann – Genoveva Shostakovich – Song of the Forests Strauss – Friedenstag