A LAN party is a social gathering of participants with personal computers or compatible game consoles, where a local area network (LAN) connection is established between the devices using a router or switch, primarily for the purpose of playing multiplayer video games together. LAN party events differ significantly from LAN gaming centers and Internet cafes in that LAN parties generally require participants to bring your own computer (BYOC) and are not permanent installations, often taking place in general-use venues or residences.

The size of these networks may vary from as few as two people to very large gatherings of a hundred or more. Small parties can form spontaneously and take advantage of common household networking equipment, but larger ones typically require more planning, equipment and preparation, even dedicated gaming servers. As of 2020, the world record for the size of a LAN party is 22,810 visitors, set at DreamHack, in Jönköping, Sweden. LAN parties were very popular in the Late 90s and 2000s, but their decline began in the early 2010s, mainly due to the advancement of online gaming and faster internet, which made it less necessary to physically meet to play.

Usually, smaller LAN parties consist of people bringing their computers over to each other's houses to host and play multiplayer games.

These are sometimes established between small groups of friends, and hosted at a central location or one that is known to all participants. Such events are often organized quickly with little planning, and some overnight events, with some stretching into days (or even weeks). Because of the small number of players, games are usually played on small levels and/or against bots.

If the venue lacks Wi-Fi, an ad hoc network may be set up, thereby eliminating the need for a wired network. Providing refreshments is often also a duty of the host, though guests are usually asked to contribute. In larger parties where participants may not all know each other personally, an entry fee may even be charged. Another tradition of some small groups is to purchase large amounts of fast food for consumption over many days. Many LAN participants will also bring food or drinks to consume over the course of the party—though they can be held at any hour, many LAN parties begin late in the evening and run through the next morning, making energy drinks a popular choice.

When some of the participants cannot be present or when merging a few LAN parties together, VPN software such as Hamachi can be used to arrange computers over the Internet so they appear to be on the same LAN.

Normally, the host will host the games but sometimes at very small LAN parties (e.g. 2 or 3 people) all participants will connect to an online internet server and add a word in front of their name to tell everyone else that they are a clan or group. At bigger LANs (e.g. 5 or more people) the host or a friend of the host will use a spare PC as a game server to serve all the participants. Usually the host and/or the owner are administrators.

The group can play together in another server as well if they wish as long as they are in the same LAN.