Altar may refer to:
- Altar (planet), one of the eight planets formed from the living world of Quire during the Miracle of the Mirage.
- Altar (Lone Marble Group), a specific mech model that harnesses the power of the Kalmeria Particle.
- Altar (mech type), a generic type of mech based on and named after the specific model, commonly seen during PALISADE.