An empire was a form of government which encompassed multiple nation-states and whose head of state was typically an emperor.
Earth empires
- Austrian Empire
- British Empire
- Byzantine Empire
- Chinese Empire
- Empire of Japan
- French Empire
- Incan Empire
- Mughal Empire
- Ottoman Empire
- Persian Empire
- Prussian Empire
- Roman Empire
Planetary empires
Interstellar empires
- Ajir Empire
- Akerian Empire
- Alsuran Empire
- Arret Empire
- Chodak Empire
- Empire of Orion
- Empire of Thrace
- Iconian Empire
- Karg Empire
- Karsid Empire
- Kelvan Empire
- Khnndak Empire
- Klingon Empire
- K'tralli Empire
- Lhiaarian Empire
- Lyaksti Empire
- MacMurray Empire
- Maurya Empire
- M'dok Empire
- Miradi Empire
- M'Tezir Empire
- Nax Empire
- Orion Empire
- Qavok Empire
- Romulan Star Empire
- Sarkassian Empire
- Selakar Empire
- Shi'ar Empire
- Tandaran Empire
- Tarn Empire
- Terran Empire
- Thallonian Empire
- Tomariian Empire
- Vulcan-Andorian Empire
- Yemai Empire