中音单簧管（Alto Clarinet）单簧管的变种乐器，介於单簧管及低音单簧管之间的中音乐器。发明初期曾出现不同的调式，现时大都统一为E♭调。

现任职于洛杉机公共图书馆，同时亦是乐器鉴定家艾伯特·赖斯（Albert Rice）指出最早有文献记载中音单簧管的，可追溯至1740年。其调性为G调，喇叭口呈散开状。但却未有留下任何实物。

德国人艾云·穆勒（Iwan Müller）和葛兰索（Heinrich Grenser）被认为是首先发明中音单簧管的人物。他们既是首批专注单簧管的制作者，两人又一同工作，且一生都致力改造及创造乐器。葛兰索于1793年发明低音单簧管。1809年，穆勒首先研发出有16孔的F调中音单簧管；在美国有数据显示亦有另一批人独立研发中音单簧管。现时收藏在大都会艺术博物馆内展有一件1820年代制成的乐器，外貌似巴松管但使用单簧管的指法，而调性是E♭调。

The alto clarinet is a woodwind instrument of the clarinet family. It is a transposing instrument pitched in the key of E♭, though instruments in F (and in the 19th century, E) have been made. In Europe it is sometimes called a tenor clarinet. In size it lies between the soprano clarinet and the bass clarinet, to which it bears a greater resemblance in that it typically has a straight body (made of Grenadilla or other wood, hard rubber, or plastic), but a curved neck and bell made of metal. All-metal alto clarinets also exist. In appearance it strongly resembles the basset horn, but usually differs in three respects: it is pitched a tone lower, it lacks an extended lower range, and it has a wider bore than many basset horns.