3Kingdoms, abbreviated 3K, is a MUD, a text-based online role-playing game, founded in 1992.

[1] The MUD has a cross-genre setting; the eponymous three kingdoms are Fantasy, Science Fiction, and Chaos, the latter following an anything-goes satirical theme.

[6] The selection of guilds reflects the cross-genre setting, ranging from fantasy commonplaces such as knights, priests (formerly called clerics), mages, and necromancers to Jedi, cyborgs, Fremen and changelings (formerly called the animal guild).

[2] The MUD has received positive critical response for its friendliness to and accommodation of new players,[2][3] and has been noted as "well-loved and full of life".

[5] 3K is an LPMud running on the LDMud game driver with an unnamed custom mudlib.