The Rhapsody on a Theme of Paganini, Op. 43, (Russian: Рапсодия на тему Паганини, Rapsodiya na temu Paganini) is a concertante work written by Sergei Rachmaninoff for piano and orchestra, closely resembling a piano concerto, all in a single movement. Rachmaninoff wrote the work at his summer home, the Villa Senar in Switzerland, according to the score, from 3 July to 18 August 1934. Rachmaninoff himself, a noted performer of his own works, played the piano part at the piece's premiere on 7 November 1934, at the Lyric Opera House in Baltimore, Maryland, with the Philadelphia Orchestra conducted by Leopold Stokowski.
Rachmaninoff, Stokowski, and the Philadelphia Orchestra made the first recording, on 24 December 1934, at RCA Victor's Trinity Church Studio in Camden, New Jersey. The English premiere on 7 March 1935 at Manchester Free Trade Hall also featured Rachmaninoff with The Hallé conducted by Nicolai Malko. The best-known variation in the piece is the 18th variation, frequently selected in isolation in classical music compilations.