Kaikhosru Shapurji Sorabji (born Leon Dudley Sorabji; 14 August 1892 – 15 October 1988) was an English composer, music critic, pianist and writer. He was one of the 20th century's most prolific piano composers.

As a composer and pianist, Sorabji was largely self-taught, and he distanced himself from the main currents of contemporary musical life early in his career. He developed a highly idiosyncratic musical language, with roots in composers as diverse as Busoni, Debussy and Szymanowski, and he dismissed large portions of the established and contemporary repertoire.

A reluctant performer, Sorabji played a few of his works in public between 1920 and 1936, thereafter "banning" performances of his music until 1976. Since very few of his compositions were published during those years, he remained in public view mainly by writing essays and music criticism, at the centre of which are his books Around Music and Mi contra fa: The Immoralisings of a Machiavellian Musician. He had a tendency to seclusion, and in the 1950s he moved from London to the village of Corfe Castle, Dorset, where he spent most of the rest of his life quietly.

Sorabji's music is characterised by frequent use of polyrhythms, complex juxtaposition of tonal and atonal elements, and copious ornamentation. Many of his works contain sections employing strongly contrasting approaches to musical architecture; some of them use baroque forms, while others are athematic. His musical output consists of over 100 compositions, ranging from aphoristic pieces to works spanning several hours. Most are for piano solo or feature an important piano part, but he also composed for orchestra, chamber ensembles, organ and other instruments. Partly because of this, Sorabji has been described as a descendant of a tradition of composer-pianists such as Frédéric Chopin, Franz Liszt and Charles-Valentin Alkan.