A military occupation was the takeover of all or part of the territory of another recognized government by a military power. (DS9: "Things Past")
Kor served as the military governor of Organia, during the Klingon Empire's brief occupation of the planet in 2267. (TOS: "Errand of Mercy")
During the 24th century, the Cardassian Union occupied numerous planets to provide it with natural resources which it lacked on its own worlds. The most notable example was the Occupation of Bajor. (DS9: "Emissary", "Duet")
In 2373, the Dominion aligned itself with Cardassian Union. Nearing the end of the Dominion War, their presence was seen as an occupation of Cardassian territory as opposed to a mutual alliance and sharing of worlds, due to the Dominion's utter disregard for the Cardassians. (DS9: "By Inferno's Light", "The Changing Face of Evil")