Niccolò Castiglioni (17 July 1932 – 7 September 1996) was an Italian composer, pianist, and writer on music.
His student compositions were marked by Stravinsky's neo-classicism, but after graduation his style changed under the influence of the Second Viennese School.
The Impromptus I–IV, identified by the composer as his first true opus, abandoned these expressionistic tensions, and these four short pieces exhibit a close relationship to Webern's aphoristic style, while also moving closer to the European avant garde.
Personal contact with Luciano Berio at the RAI electronic music studio in Milan also influenced Castiglioni's direction at that time, and his attendance at the Darmstädter Ferienkurse completed this development.
Among his many students are Armando Franceschini, Giampaolo Testoni and Carlo Galante, Alfio Fazio, Aldo Brizzi, Matteo Silva and Esa-Pekka Salonen.