John Field (26 July 1782 [?], baptised 5 September 1782 – 23 January 1837) was an Irish pianist, composer, and teacher. He was born in Dublin into a musical family, and received his early education there. The Fields soon moved to London, where Field studied under Muzio Clementi. Under his tutelage, Field quickly became a famous and sought-after concert pianist; together, master and pupil visited Paris, Vienna, and St. Petersburg. Ambiguity surrounds Field's decision to remain in the Russian capital, but it is likely that Field acted as a sales representative for the Clementi Pianos.

Field was very highly regarded by his contemporaries and his playing and compositions influenced many major composers, including Frédéric Chopin, Johannes Brahms, Robert Schumann, and Franz Liszt. Field is best known as the instigator of the nocturne, but there is evidence to suggest that this is a posthumous accolade. Although little is known of Field in Russia, he undoubtedly contributed substantially to concerts and teaching, and to the development of the Russian piano school.