The Great Houses (tuqmey Dun) were a Klingon feudalistic social organization that dominated the Klingon Empire. Each House was usually led by the eldest male of the ruling family, for whom the House was named. His wife was the Mistress of the Great House, who usually oversaw the running of the household and approved all marriages into the family. Traditionally the ruling family was of noble descent, although in the late 24th century that was not always the case. The Great House also included various properties and holdings, and commanded military forces. The rulers of the 24 most powerful Great Houses formed the Klingon High Council.
When the head of a Great House died, either in battle or of natural causes, leadership of the House passed to his heir, usually his son. If he was defeated in honorable combat, his wife also had the right to choose his victor as the new head of her House (see also: brek'tal ritual). If the head of the House left no male heir, the High Council could arrange special dispensation for someone else to rule the House, such as the Mistress. (DS9: "The House of Quark") It was possible for individuals unrelated by blood to join a Great House, by consent of the House's head. (TNG: "The Bonding"; DS9: "Soldiers of the Empire"; see also: R'uustai)
Great Houses which were gravely dishonored by the actions of their rulers could be disbanded, and their holdings claimed by other Houses.
- House of Antaak
- House of D'Ghor
- House of Duras
- House of Grilka (temporarily "House of Quark", formerly House of Kozak)
- House of Konjah
- House of Kor
- House of Kozak (now House of Grilka)
- House of Martok
- House of Mo'Kai
- House of Mogh
- House of Noggra
Ronald D. Moore stated: "We've never explored the hows and whys regarding the naming of Klingon Houses. The House of Mogh reference was probably something that Worf carried on out of respect for his deceased father. This might be the right of a son – to perpetuate a single name for the House instead of supplanting it with his own." (AOL chat, 1997)