Role-playing games (commonly abbreviated RPGs) derived their name through the central part of their unique nature. Each participant in the game plays the role of a character frequently (but not always) created by them. Players engage in adventures that are directed by another entity, which may be another person or a complex computer program. Unlike traditional games, players do not compete with each other to see who wins, but instead collaborate in order to tell a story and evolve the characters. The games may take place in a fantasy environment full of dragons, a future environment full of computers and advanced weapons, a current reality in which vampires and werewolves walk among us, or many other worlds.

In tabletop RPGs, participants gather in one location. Players generally construct their characters by ascribing numerical values to certain characteristics. This information is tracked on a document called a character sheet. A strong but dumb brute may have a 20 in strength and a 6 in intelligence, while a feeble but clever witch may have a 19 in wisdom and a 4 in stamina. The challenges the players face, and the characters the players meet, are controlled by a person known as the Game Master (GM) or Dungeon Master (DM). Actions, interactions and consequences are described verbally. In dice-controlled games, the GM places a numerical value on an action. Players determine the success or failure of their actions by rolling dice. Their dice roll, combined with their existing points in an area, gives information on whether they have succeeded or failed in their action and adds an element of chance to the game.

Live-action role-playing games (LARPs) are similar to tabletop RPGs. Players generally dress up in costume and act out their character's actions in an environment that evokes the setting of the game. Some use foam weapons to replicate combat; others use rock-paper-scissors to determine the outcome of an action or conflict.

Online role-playing games are known as MMORPGs. In these games, players use a computer connected to the Internet, and interact both with other players around the world and with non-player characters run by the computer system. These games have achieved widespread popularity.