A role-playing game (RPG) is a broad family of games in which players assume the roles of characters, or take control of one or more avatars, in a fictional setting. Actions taken within the game succeed or fail according to a formal system of rules and guidelines.

The original form, sometimes called the pen-and-paper RPG, is conducted through speech, whereas in live action role-playing games (LARP) players physically perform their characters’ actions. In both of these forms, an arranger called a game master (GM) usually decides on the rules and setting to be used and acts as referee, while each other player plays the role of a single character. At the heart of these formats is in-character participation in a collaborative narrative. Several varieties of RPG also exist in electronic media, including text-based MUDs and their graphics-based successors, massively multiplayer online role-playing games (MMORPGs).

Role-playing games also include offline role-playing video games in which players control a character or team who undertake quests, and whose capabilities advance using statistical mechanics. These games often share settings and rules with pen-and-paper RPGs, but do not enable the same collaborative storytelling.

Despite this variety of forms, some game forms such as trading card games and wargames that are related to role-playing games may not be included. Role-playing activity may sometimes be present in such games, but it is not the primary focus. The term is also sometimes used to describe roleplay simulation games and exercises used in teaching, training, and academic research.