Mask is an artefact normally worn on the face, typically for protection, concealment, performance, or amusement. Masks have been used since antiquity for both ceremonial and practical purposes. They are usually, but not always, worn on the face, although they may also be positioned for effect elsewhere on the wearer's head.

Un masque est le plus souvent un objet adapté à la forme du visage, porté devant ce dernier. Il permet entre autres, de se déguiser, de s'orner, de rester inconnu. 

The 5000-year-old Sumerian mask of Warka is believed to be the oldest surviving mask. It was looted from the Iraqi National Museum in Baghdad, but was recovered in 2003.

The word "mask" came via French masque and either Italian maschera or Spanish máscara. Possible ancestors are Latin (not classical) mascus, masca = "ghost"; Hebrew masecha= "mask"; Arabic maskharah مَسْخَرَۃٌ = "jester", "man in masquerade", maskhara مَسْخَرَ = "he ridiculed, he mocked", masakha مَسَخَ = "he transfomed" (transitive).

Masked characters, usually divinities, are a central feature of Indian dramatic forms, many based on depicting the epics Mahabharata and Ramayana. Countries that have had strong Indian cultural influences – Cambodia, Burma, Java, Thailand, Vietnam – have developed the Indian forms, combined with local myths, and developed their own characteristic styles.

The masks are usually highly exaggerated and formalised, and share an aesthetic with the carved images of monstrous heads that dominate the facades of Hindu and Buddhist temples. These faces or Kirtimukhas, 'Visages of Glory', are intended to ward off evil and are associated with the animal world as well as the divine. During ceremonies these visages are given active form in the great mask dramas of the South and South-eastern Asian region.