Fan labor, also called fan works, are the creative activities engaged in by fans, primarily those of various media properties or musical groups. These activities can include creation of written works (fiction, fan fiction and review literature), visual or computer-assisted art, films and videos, animations, games, music, or applied arts and costuming.

Although fans invest significant time creating their products, and fan-created or fanmade products are "often crafted with production values as high as any in the official culture," most fans provide their creative works as amateurs, for others to enjoy without requiring or requesting monetary compensation. Fans respect their gift economy culture and are often also fearful that charging other fans for products of their creativity will somehow fundamentally change the fan-fan relationship, as well as attract unwanted legal attention from copyright holders. The skills that fans hone through their fan works may be marketable, and some fans find employment through their fan works.

In recent years, media conglomerates have become more aware of how fan labor activities can add to and affect the effectiveness of media product development, marketing, advertising, promotional activities, and distribution. They seek to harness fan activities for low-cost and effective advertisements (such as the 2007 Doritos Super Bowl Ad contest) at the same time as they continue to send out cease and desist to the creators of amateur fan products—threatening legal action whose basis is increasingly being questioned by fandom rights groups like the Organization for Transformative Works, which assert the transformative and therefore legal nature of fan labor products.

In the fandom subgroups science fiction fandom and media fandom, fan labor activities may be termed fanac (from "fannish activities"), a term that also includes non-creative activities such as managing traditional science fiction fanzines (i.e., not primarily devoted to fan fiction), and the organization and maintenance of science fiction conventions and science fiction clubs.

A more general and internet focused form of "fan work" is user-generated content, which became popular with the Web 2.0, often also a form of virtual volunteering.

Fans use all art forms to express their creativity with regard to their fandoms.

Fan fiction is the most widely known fan labor practice, and arguably one of the oldest, beginning at least as early as the 17th century. Fan fiction stories ("fan fic") are literary works produced by fans of a given media property, rather than the original creator. They may expand on an original story line, character relationship, or situations and entities that were originally mentioned in the original author's work. Works of fan fiction are rarely commissioned or authorized by the original work's owner, creator, or publisher, and they are almost never professionally published.

The rise of online repositories built to archive and deliver fan fiction has resulted in a new activity: fandom analytics. This fan labor practice is focused on the analysis and visualization of the use of content tags and categories, along with other metrics, such as hit and word counts in order to discuss and forecast trends and variations within and across fandoms.