Ermanno Wolf-Ferrari (January 12, 1876 - January 21, 1948) was an Italian composer. He is best known for his comic operas, I quattro rusteghi (1906) and Il segreto di Susanna (1909). A number of his works were based on plays by Carlo Goldoni.

Wolf-Ferrari was born in Venice. His father was a painter, and sent Ermanno to Rome to study art. From there he went to Munich, and it was while there that he decided to concentrate instead on music, taking lessons from Josef Rheinberger. He wrote his first works in the 1890s.

In 1900, having failed to have two previous efforts published, Wolf-Ferrari saw the first performance of one of his operas, Cenerentola, which was given in Venice. This was a failure at its premiere, although a later performance in Bremen was a success, setting a pattern for his later work, much of which was premiered in Germany and was received a good deal better there than it was in his native Italy. Among these works are Le donne curiose (1903), I quattro rusteghi (1906), and Il segreto di Susanna (1909), all of them comedies, and all of them successful at their German premieres.

With the outbreak of World War I, Wolf-Ferrari moved to Zürich and composed much less, though he still wrote another comedy, Gli amanti sposi (1916). He did not really pick up his rate of output until the 1920s, when he wrote Das Himmelsklied (1925) and Sly (1927), the latter based on William Shakespeare's The Taming of the Shrew.

As well as his operas, Wolf-Ferrari wrote a number of instrumental works, mainly at the very beginning and very end of his career. Only his violin concerto has ever been performed with anything approaching regularity, though he also wrote Idillio-concertino (essentially a chamber symphony), various pieces of chamber music including a piano quintet and two piano trio, two violin sonatas and a number of works for the organ amongst others.

Wolf-Ferrari's work is not performed very widely, although he is generally thought of probably the finest writer of Italian comic opera of his time. His works often recall the opera buffa of the 18th century, although he also wrote more ambitious works in the manner of Pietro Mascagni, which are thought of less well. Much of his work has been ignored, although a performance in 1999 of Sly by the Washington Opera (the work's American premiere) marked something of a slight revivial of interest in his works.