This article is on masks as an article of clothing; there is another article on the computer science term 'mask'.

A mask is a piece of material worn on the face.

Masks have been used since antiquity for both ceremonial and practical purposes

Ceremonial uses have uses in religious functions with participants wearing them to represent certain spiritual figures. The use of masks in the dramatic plays in Ancient Greece evolved from this purpose. The mask is also one of the defining characteristics of the Noh theatre of Japan.

The practical uses of masks include protection and disguise.

The protection function of a mask takes to two predominate ways.

• Filter masks and gas masks protect the wearer by preventing harmful substances and/or organisms from being inhaled by filtering them out.
• Some masks are made of durable material intended to shield the wearer's face from flying objects, exposure to surrounding environment or radiation while still allowing vision. These include the ice hockey goalie mask, a welders mask, a divers mask, a spacesuit mask etc.

Criminals often use masks to avoid identification when they commit crimes. In many jurisidictions, it is an additional criminal offense to wear a mask in committing a crime.

See also:

• headgear
• list of hats and headgear