Oceania is one of the three superstates in George Orwell's novel Nineteen Eighty-Four, and is the location of the novel's version of London, where Winston Smith, the main character, lives.

It is apparently composed of the Americas, Ireland and Great Britain (collectively called Airstrip One in the novel), Australia, New Zealand, Papua New Guinea and the southern half of Africa below the River Congo. It also controls — to different degrees, at various times during the course of its eternal war with Eurasia and Eastasia — the polar regions, India and the islands of the Pacific. It is described in The Theory and Practice Of Oligarchical Collectivism by Emmanuel Goldstein, Oceania's declared Public Enemy #1, as resulting from the merging of the British Empire and the United States. Goldstein's book also states that Oceania's primary natural defence is the sea surrounding it. This may be the reason why the Party highlights the Floating Fortresses.

It occasionally conquers the rest of Africa, but is later driven back by Eurasia. Oceania lacks a single capital, although what could be seen as regional capitals such as London and apparently New York City are in place.

The ruling doctrine of Oceania is Ingsoc, the Newspeak term for English Socialism, which is ultimately devoted to the naked exercise of power. Its nominal leader is Big Brother, possibly a leader of the revolution who has now died, or the way in which the Party chooses to express itself. The cult of leadership is maintained through Big Brother's function as a focal point for love, fear, and reverence, emotions which are more easily felt towards an individual than towards an organization.

The chief language of Oceania is English (officially Oldspeak) and a minimalist derivation of it, known as Newspeak. The restructuring of the language is intended to ultimately eliminate the possibility of non-Oceanic political thought.

The society of Oceania is sharply stratified into three groups, the small power-seeking Inner Party, the more numerous and highly indoctrinated Outer Party, and the large body of politically meaningless and mindless Proles. Except for certain rare exceptions like Hate Week, the proles remain essentially outside Oceania's political society.

It should be noted that almost all of the information about Oceania beyond London is given to the reader through government or Party sources, which by the very premise of the novel are unreliable. "Oceania," may control only Britain and possibly some of it's colonies, or it may be the sole unchallenged world government. The war, similarly, may be entirely, or in part, fiction. The whole Earth may well be controlled by one state which pretends to exist as three states, perpetually warring in order to maintain the climate of fear needed for totalitarian rule. By its references and the period in which it was written, Big Brother and Goldstein can also be compared with Joseph Stalin and Leon Trotsky whose conflict over the future of international Communism was well known and a subject of constant debate within the movements of the postwar international Left.

Oceania's national anthem is Oceania, Tis For Thee which, in one of the three film versions of the book, takes the form of a crescendo of organ music along with operatic lyrics. The lyrics are sung in English, and the song shares many similarities with Soviet anthems. The song also is reminiscent of God Save the Queen and its American cousin My Country Tis of Thee.