Dmitri Nikolaevich Smirnov (2 November 1948 – 9 April 2020) was a Russian-British composer and academic teacher, known for his operas, symphonies, string quartets, chamber music, and vocal works ranging from songs to oratorios. Born in Minsk, Byelorussian SSR, Soviet Union, to a family of opera singers, Smirnov spent much of his childhood in Ulan-Ude and Bishkek. He studied composition at the Moscow Conservatory and privately with Philip Herschkowitz, a student of Anton Webern.

Smirnov's career included work as an editor for Sovietski Kompositor and later as a freelance composer. He gained international recognition after winning first prize for his composition "Solo for Harp" at the International Harp Week in Maastricht in 1976. However, in 1979, he was blacklisted as one of "Khrennikov's Seven" for participating in unapproved Soviet music festivals in the West.

In 1991, Smirnov moved to England, where he held positions such as composer in residence at the University of Cambridge's St John's College and visiting professor at Keele University. From 2003, he taught at Goldsmiths College, University of London. Many of his compositions were inspired by the art and poetry of William Blake, including operas and symphonies. His works have been performed by prominent conductors and orchestras worldwide. Smirnov was married to composer Elena Firsova, and they had two children.