The String Quartets, Op. 50, were composed by Joseph Haydn in 1787. The set of six quartets was dedicated to King Frederick William II of Prussia. For this reason the set is commonly known as the Prussian Quartets. Haydn sold the set to the Viennese firm Artaria and, without Artaria's knowledge, to the English publisher William Forster. Forster published it as Haydn's Opus 44. Haydn's autograph manuscripts for Nos. 3 to 6 of the set were discovered in Melbourne, Australia, in 1982.

Franz Joseph Haydn was an Austrian composer of the Classical period. He was instrumental in the development of chamber music such as the string quartet and piano trio. His contributions to musical form have led him to be called "Father of the Symphony" and "Father of the String quartet".