A wig, from the French "(per)ruque", is a head of hair made from horse-hair, human hair, wool, feathers, buffalo hair, or synthetic, worn on the head for fashion or various other aesthetic and stylistic reasons, including cultural and religious observance. The word wig is short for periwig and first appeared in the English language around 1675.

Some people wear wigs to disguise the fact that they are bald; a wig may be used as a less intrusive and less expensive alternative to therapies for restoring hair. Wigs may also be used as a cosmetic accessory, sometimes in a religious context. Actors, on the other hand often wear costume wigs in order to better portray a character.