A missa brevis (Latin, pl. missae breves) is, literally, a "short Mass". It can refer to several forms of the mass, from the "telescoped" Viennese masses of Haydn and Mozart to the Low Mass (called messe basse in French and Deutsche Singmesse in German), or in the specifically Lutheran sense to a mixed setting. Nowadays it is generally understood as a setting of the ordinary mass that does not include the Credo and is a popular genre of twentieth century choral composition.

The "Credo" is often omitted, but these movements may be included:

Note that although the Sanctus and Benedictus form a single part of the liturgical Mass, composers often choose to set this as two (or more) musical parts.

The simultaneous recitation of different sections of long texts in various voices is a feature of some missae breves. This is especially characteristic of Austrian masses which usually include the Credo; this technique is applied to the Gloria as well.

The Lutheran missa brevis often consists of either a Kyrie/Gloria (as in J. S. Bach's four missae breves) or a Sanctus/(Benedictus)/Agnus (as in Brahms' Missa canonica), reflecting the widespread practice of mixing settings.

Mozart also composed a missa longa (the opposite of a missa brevis) which simply takes more time to perform, and is more elaborate.

A messe basse is simply a "Low Mass", which may be entirely spoken in a low voice to the accompaniment of music. It is the equivalent of the Deutsche Singmesse. Fauré's Messe basse and Schubert's Deutsche Messe, D. 872, are famous examples.

Notable examples of the missa brevis form are by composers such as: