A Wiki is computer software that allows users to easily create, edit and link web pages.

Wikis are often used to create collaborative websites, power community websites, and are increasingly being installed by businesses to provide affordable and effective Intranets or for use in Knowledge Management. Ward Cunningham, developer of the first wiki, WikiWikiWeb, originally described it as "the simplest online database that could possibly work".

One of the best-known wikis is Wikipedia.