The German Fach (pl. Fächer, literally "compartment" or also "subject (of study)", here in the sense of "(vocal) specialization") (German pronunciation: [ˈfax, ˈfɛçɐ]) system is a method of classifying singers, primarily opera singers, according to the range, weight, and color of their voices. It is used world wide, but primarily in Europe, especially in German-speaking countries and by repertory opera houses.

The Fach system is a convenience for singers and opera houses. It prevents a singer from being asked to sing roles which he or she is incapable of performing. Opera companies keep lists of available singers by Fach so that when they are casting roles for an upcoming production, they do not inadvertently contact performers who would be inappropriate for the part.

Below is a list of Fächer, their ranges as written on sheet music, and roles generally considered to appropriate to each. When two names for the Fach are given, the first is in more common use today. Where possible, an English and/or Italian equivalent of each Fach is listed; however, not all Fächer have ready English or Italian equivalents. Note that some roles can be sung by more than one Fach and that many singers do not easily fit into a Fach: for instance some sopranos may sing both Koloratursopran and Dramatischer Koloratursopran roles. In addition, roles traditionally more difficult to cast may be given to a voice other than the traditional Fach. For instance, the "Queen of the Night" is more traditionally a dramatic coloratura role, but it is difficult to find a dramatic coloratura to sing it (particularly given the extreme range). Therefore, the role is often sung by a lyric coloratura.