Ars nova (Latin for new art) refers to a musical style which flourished in the Kingdom of France and its surroundings during the Late Middle Ages. More particularly, it refers to the period between the preparation of the Roman de Fauvel (1310s) and the death of composer Guillaume de Machaut in 1377. The term is sometimes used more generally to refer to all European polyphonic music of the fourteenth century. For instance, the term "Italian ars nova" is sometimes used to denote the music of Francesco Landini and his compatriots, although Trecento music is the more common term for the contemporary 14th-century music in Italy. The "ars" in "ars nova" can be read as "technique", or "style". The term was first used in two musical treatises, titled Ars novae musicae (New Technique of Music) (c. 1320) by Johannes de Muris, and a collection of writings (c. 1322) attributed to Philippe de Vitry often simply called "Ars nova" today. Musicologist Johannes Wolf first applied to the term as description of an entire era (as opposed to merely specific persons) in 1904.

The term ars nova is often used in juxtaposition to two other periodic terms, of which the first, ars antiqua, refers to the music of the immediately preceding age, usually extending back to take in the period of Notre Dame polyphony (from about 1170 to 1320). Roughly, then, ars antiqua refers to music of the thirteenth century, and the ars nova that of the fourteenth; many music histories use the terms in this more general sense.

The period from the death of Machaut (1377) until the early fifteenth century, including the rhythmic innovations of the ars subtilior, is sometimes considered the end of, or late, ars nova but at other times an independent era in music. Other musical periods and styles have at various times been called "new art." Johannes Tinctoris used the term to describe Dunstaple; however, in modern historiographical usage, it is restricted entirely to the period described above.