Outworld is one of the many realms of reality in the Mortal Kombat universe. A dark and desolate land, it has long been the victim of various despotic tyrants that have ruled the realm through violence and terror. It is home to various races and a menagerie of monstrous beings, many of which are still unknown.
Outworld has also expanded over the course of millennia as its rulers - most notably Onaga and Shao Kahn - have waged endless war against countless other realms across the universe, conquering them and merging them with Outworld. As such, not all of Outworld has been charted as the realm consists of countless layers made up of multiple worlds that have been annexed either as a result of invasion or through defeat in the Mortal Kombat tournament.
- Shao Kahn's Fortress - An imposing, ironclad stronghold from which Shao Kahn governs his empire.
- Z'Unkahrah - Capital city of Outworld.
- Living Forest - Woodland inhabited by sentient trees.
- Dragon King's Temple - A forbidding structure set atop Dragon Mountain where the monks of the Dragon King Onaga would gather in worship. It was here that the resurrected Onaga enacted his plan to combine the Kamidogu in order to become the One Being.
- Golden Desert - Arid desert landscape.
- Kuatan - Subterranean kingdom of the Shokan.
- Lei Chen - A fortified township ruled by Overlord Zeffeero.
- Quan Chi's Fortress - An imposing dark tower that served as Quan Chi's lair in Mortal Kombat: Deadly Alliance.
Native sentient races
- Outworlder - The most common race of Outworld is a humanoid species that physically resemble humans. What sets Outworlders apart from humans is their natural inclination towards magic as well as their longevity. They are said to live for thousands of years and age considerably slower than humans.
- Cryomancer - A humanoid race that possessed a natural affinity for manipulating ice. This race is now extinct, though the Earthrealm warrior Sub-Zero is supposedly a descendant of this race.
- Shokan - A race of four-armed human-dragon hybrids. They reside within the subterranean kingdom of Kuatan and have long served Shao Kahn as his mightiest enforcers.
- Centaurian - A race that closely resembles the Centaurs of ancient Greek mythology in Earthrealm. They have long been blood enemies of the Shokan and yet serve Shao Kahn as hunters and exterminators.
- Moroi - A race of vampires that originally came from the world of Vaeturnus before it was conquered by Shao Kahn and merged with Outworld.
- Saurian - Also known as Raptors. Originally from Earthrealm in ancient times, they migrated to Zaterra after the near-annihilation of their race during the war between Shinnok and the Elder Gods. They would later be wiped out when Shao Kahn annexed their home.
- Tarkata - A nomadic race of mutant hybrids originating from the Netherrealm which have long since populated the wastelands of Outworld.
- Edenian - A humanoid race believed to be descended from the Gods themselves. Like Outworlders, they are naturally magically inclined and live over a span of millennia. Originally native to Edenia until Shao Kahn's forces won ten consecutive Mortal Kombat tournaments and conquered the realm. However, in recent times the merger between Outworld and Edenia has been reversed and most of the Edenians have returned to their homeworld.
- Osh-Tekk - A warrior race that originated from a gold-dominated realm before Kahn's conquest. For a long time they lived under Kahn's rule, but since Kotal Kahn rose to power, loyalists to the former emperor have waged a campaign of extermination against the Osh-Tekk. Kotal Kahn is now the last of his kind.
- Kytinn - A race of humanoid insects from the realm of Arnyek.