Milton Mesirow, much better known as Mezz Mezzrow (9 November, 1899 - 5 August, 1972) was an American Jewish jazz clarinetist and alto saxophonist from Chicago, Illinois.

He financed a recording session with Tommy Ladnier and Sidney Bechet session and recorded a number of times with Bechet. He briefly acted as manager for Louis Armstrong.

However, he was more well-known for his drug-dealing than his musical prowess. In fact, he was so well-known in the jazz community for selling marijuana that "Mezz" became slang for marijuana.

He praised and admired the African-American style. In his autobiography, Mezzrow writes that from the moment he heard jazz he "was going to be a Negro musician, hipping [teaching] the world about the blues the way only Negroes can."

There is evidence that Mezzrow, despite being white, eventually came to think of himself as a black man. He married a black woman and lived in Harlem. He called himself a "voluntary Negro". When he served a prison sentence for dealing marijuana, he insisted to the guards that he was a negro and was transferred to the negro section.

Mezzrow was lifelong friends with a French jazz critic named Hugues Panassié, and consequently pent the last twenty years of his life living in Paris. Mezzrow is best known for his autobiography, Really the Blues, published in 1946.