Live action role-playing (LARP) is a form of role-playing game where the participants physically portray their selected characters.(Tychsen et al. 2006:255) "LARPs can be viewed as forming a distinct category of RPG because of two unique features: (a) The players physically embody their characters, and (b) the game takes place in a physical frame. Embodiment means that the physical actions of the player are regarded as those of the character. LARP participants may dress in the costume of their character and carry appropriate physical props (e.g., an 18th century militia LARP participant may wear a military uniform and carry a musket). Whereas in a RPG played by a group sitting around a table, players describe the actions of their characters (e.g., "I run to stand beside my friend"); in an equivalent situation in a LARP, a player would physically run to the appropriate point within the game space." The players pursue goals within a fictional setting represented by real-world environments while interacting with each other . The outcome of player actions may be mediated by game rules or determined by consensus among players. Event arrangers called gamemasters decide the setting, specify the rules to be used, and facilitate play.

The first LARPs took place in the late 1970s, inspired by tabletop role-playing games and genre fiction. The activity spread internationally during the 1980s and has diversified into a wide variety of styles. Play may be very game-like or may be more concerned with dramatic or artistic expression. Gamemasters may design events to achieve educational or political goals. The fictional genres used vary greatly, from realistic modern or historical settings to fantastic or futuristic eras. Production-values, though sometimes minimal, can involve elaborate venues and costumes. LARPs range in size from small private events lasting a few hours, to large public events with thousands of players lasting for days.

Terminology LARP has also been referred to as live role-playing (LRP), interactive literature, and free form role-playing. Some of these terms are still in common use; however, LARP has become the most commonly accepted term.(Tychsen et al. 2006:255) "LARP ... is the commonly accepted term in the gaming community." It is sometimes written in lowercase, as larp.(Fatland 2005:1) "The non-Nordic reader should, however, keep in mind that there are some differences between the Nordic and Anglo-American uses of English when talking about larp. Most importantly, we treat 'larp' as a word in its own right, not an acronym (L.A.R.P.), and it is spelt lower-case."

Play overview The participants in a LARP physically portray characters in a fictional setting, improvising their characters' speech and movements somewhat like actors in improvisational theatre.(Kilgallon et al. 2001:1) "A live action roleplaying game is a cross between a traditional 'tabletop' roleplaying game and improvisational theatre." This is distinct from tabletop role-playing games, where character actions are described verbally. LARPs may be played in a public or private area and may last for hours or days. There is usually no audience.(Falk & Davenport 2004:128) "...live role-playing games are devoid of the audience concept." Players may dress as their character and carry appropriate equipment, and the environment is sometimes decorated to resemble the setting.(Falk & Davenport 2004:131) "The LRP player, like a stage actor, is a person who under-goes a transformation into a character. The character's costume and accessories, or kit, aids this transformation ... Physical structures may be used as game locations, and sometimes even purposely constructed to enhance the game world ... Players frequently use physical artifacts as props and tools in their role-play, primarily to back up their character roles." LARPs can be one-off events or a series of events in the same setting, and events can vary in size from a handful of players to several thousand.(Tychsen et al. 2006:259) "Most LARPs are either scenarios (or single-shots) or campaigns (also known as chronicles)"(Tychsen et al. 2006:258) "Games range in size from a handful to more than 4,000 players"

Arrangers called gamemasters (GMs) determine the rules and setting of a LARP, and may also influence an event and act as referees while it is taking place.(Tychsen et al. 2005:216) "In order to play, the players must have a fictional setting... In essence, the GM creates the magical circle around the game."(Montola, Stenros & Waern 2009) "Runtime game mastering is the process of influencing the flow of a game in real time."(Tychsen et al. 2005:218) "The GM may or may not be responsible for enforcing the rules between players... The GM can also be responsible of hunting down cheaters or other rule breakers." The GMs may also do the logistical work, or there may be other arrangers who handle details such as advertising the event, booking a venue, and financial management. Unlike the GM in a tabletop role-playing game, a LARP GM seldom has an overview of everything that is happening during play because numerous participants may be interacting at once. For this reason, a LARP GM's role is often less concerned with tightly maintaining a narrative or directly entertaining the players, and more with arranging the structure of the LARP before play begins and facilitating the players and crew to maintain the fictional environment during play.(Tychsen et al. 2005:218) "[The GM is] forced to let go of the game and let it take on a life of its own outside his or her control. While based on similar principles, the requirements [are] therefore very different in practice from GMs in PnP RPGs... The GM is generally, unless the LARP is small in terms of number of participants, not responsible for keeping the narrative flow. The GM can however oversee the progress of the game and help or influence where needed... Establishing a hierarchy of GMs and NPCs to monitor the game and ensure everyone is entertained and activated within the shared game space is a typical way of controlling large fantasy LARPS. This structure is usually established before the game commences."

Participants sometimes known as the crew may help the GMs to set up and maintain the environment of the LARP during play by acting as stagehands or playing non-player characters (NPCs) who fill out the setting.(Bestul 2006:26) "Finally, a person may also participate as a type of stagehand. Though not all games will require them, it is occasionally necessary to have a support staff to help coordinate events and NPCs as a stage manager or running crew might."(Tychsen et al. 2005:216) "The environment needs to be filled out with non-player controlled characters (NPCs) Crew typically receive more information about the setting and more direction from the GMs than players do. In a tabletop role-playing game, a GM usually plays all the NPCs, whereas in a LARP, each NPC is typically played by a separate crew member.(Tresca 2010:188) "Where LARPs differ most from tabletop games is in the handling of non-player characters (NPCs). The physical performance necessary to pull off a performance in a LARP makes it impractical for a single person to handle many NPC roles. As a result, there is often a cast of characters who take on the roles of other NPCs. Unlike the players, the NPCs usually know the game's plot and have some idea of the narrative. NPCs, then, are a form of pseudo-player. They play the game, their characters have somewhat more limited goals, but they are ultimately constrained by the plot."

Much of play consists of interactions between characters. Some LARP scenarios primarily feature interaction between PCs. Other scenarios focus on interaction between PCs and aspects of the setting, including NPCs, that are under the direction of the GMs.(Young 2003:11) "The focus of interaction of larp... can be player to player or player to environment."(Tychsen et al. 2005:216) "LARP scenarios can likewise vary from detailed scripts of each participating character, to a loose association of GM-controlled NPCs in a fictional world setting."

History

LARP does not have a single point of origin, but was invented independently by groups in North America, Europe, and Australia.(Tychsen et al. 2006:256) "LARPs ... appear to have developed based on inspiration from tabletop RPGs such as Dungeons & Dragons, more or less simultaneously in North America, Europe, and Australia in the early 80s. Players from all of these continents claim to have hosted the oldest LARP, however, it appears that LARPs developed independently and with marked cultural differences." These groups shared an experience with genre fiction or tabletop role-playing games, and a desire to physically experience such settings. In addition to tabletop role-playing, LARP is rooted in childhood games of make believe, play fighting, costume parties, roleplay simulations, Commedia dell'arte, improvisational theatre, psychodrama, military simulations, and historical reenactment groups such as the Society for Creative Anachronism.

The earliest recorded LARP group is Dagorhir, which was founded in 1977 in the United States and focuses on fantasy battles. Soon after the release of the movie Logan's Run in 1976, rudimentary live role-playing games based on the movie were run at US science fiction conventions. In 1981, the International Fantasy Gaming Society (IFGS) started, with rules influenced by Dungeons & Dragons. IFGS was named after a fictional group in the 1981 novel Dream Park, which described futuristic LARPs. In 1982, the Society for Interactive Literature, a predecessor of the Live Action Roleplayers Association (LARPA), formed as the first recorded theatre-style LARP group in the US.

Treasure Trap, formed in 1982 at Peckforton Castle, was the first recorded LARP game in the UK and influenced the fantasy LARPs that followed there. The first recorded LARP in Australia was run in 1983, using the science fiction Traveller setting. In 1993, White Wolf Publishing released Mind's Eye Theatre, which is played internationally and is the most commercially successful published LARP. The first German events were in the early 1990s, with fantasy LARP in particular growing quickly there, so that since 2001, two major German events have been run annually that have between 3000 and 7000 players each and attract players from around Europe.

Today, LARP is a widespread activity internationally. Games with thousands of participants are run by for-profit companies, and a small industry exists to sell costume, armour and foam weapons intended primarily for LARP.(Tychsen et al. 2006:258) "Today, LARPing is a widespread hobby, especially within the United States and Europe, and caters to at least 100,000 players worldwide ... Professional, full-time LARP sites also exist ... a small industry has grown-up supplying latex weapons, costumes, theater props, and special effects, and numerous special effects and make-up artists work in the LARP environment for training purposes." In 2023, Dicebreaker reported that "China has developed its own LARP phenomenon in recent years. Jubensha is far more commercially successful and influential than anything we have seen before even in Nordic countries – and there is a good chance it might change our perception of what live-action roleplaying games are capable of in the future".

Purpose Most LARPs are intended as games for entertainment. Enjoyable aspects can include the collaborative creation of a story, the attempt to overcome challenges in pursuit of a character's objectives, and a sense of immersion in a fictional setting. LARPs may also include other game-like aspects such as intellectual puzzles, and sport-like aspects such as fighting with simulated weapons.