Sullivan, Sir Arthur Seymour (1842-1900), English composer, known for his comic operas written in collaboration with English playwright Sir William S. Gilbert. Sullivan was born in London.

Sullivan's first comic opera, Cox and Box (1867), revealed a notable talent for the medium. In 1871 he met Gilbert, and the two men entered into a remarkable collaboration that lasted 25 years. Together they produced 14 comic operas, including H.M.S. Pinafore (1878), The Pirates of Penzance (1879), and The Gondoliers (1889).

Musically, the Gilbert and Sullivan operas are generally considered the finest comic operas ever written to English texts. Sullivan had a notable gift for melody and for musical parody- particularly of Italian operas and English Elizabethan madrigals. He also originated new forms of comic musical settings, including the patter song, a light tune in which skillful use is made of a long, rapidly delivered text.