Eternity can refer to:
- Eternity (WAD), a 1994 map set which was considered by Doomworld as one of the Top 100 WADs of All Time.
- Eternity TC, unrelated to the above, a total conversion that is now abandoned.
- Eternity Engine, a source port originally developed for the TC but which survived it.
- Team Eternity, the group that formed to develop the Eternity TC and engine.
- E4M3: Eternity, a map in megawad Lunar Catastrophe.