Giovanni Battista Viotti (May 12, 1755 - March 3, 1824) was an Italian violinist and composer.

Viotti was a pupil of Gaetano Pugnani . He served at the court in Turin and toured as a soloist, at first with Pugnani before going to Paris alone. He was particularly popular there, and served for a time at Versailles before founding a new opera house, the Théâtre de Monsieur in 1788. When the French Revolution made the production of new opera impossible, he moved to London. He later returned to Paris, but gave up giving concerts to run a wine business. This failed however, and he worked as director of the Paris Opera from 1819 to 1821. He died in London.

Viotti was a very influential violinist. The teacher of both Pierre Rode and Pierre Baillot and an important influence on Rodolphe Kreutzer, all of whom became notable teachers themselves, he is considered the founding father of the 19th century French violin school. He also taught August Duranowski , who was an influence on Niccolò Paganini.

Viotti owned a Stradivarius violin that would eventually become known as the Viotti Strad. It is rumored that Viotti received the violin as a love token from Catherine the Great. He is also thought to have commissioned the construction of at least one fake copy of this violin. The Viotti Strad is currently being considered for sale, and the Royal College of Music has been refused lottery funding to retain the violin.

Viotti's most notable compositions are his 29 violin concertos which were an influence on Ludwig van Beethoven. One in particular, No. 22 in a minor (1792), is still very frequently performed--especially by advanced student players. Most of his music features the violin prominently: his string quartets largely ignore the balanced texture pioneered by Haydn, giving a "solo" role to the first violin. Viotti often wrote chamber music for more traditional combinations such as two violins and bass. He also wrote sonatas, songs, and other works.