Mars is the fourth planet from the Sun in the Milky Way galaxy.
- In the DC Comics universe, Mars is home to a race of sentient, shapechanging beings called Martians. They are split into two factions, the parasitic and malevolent White Martians, and the benevolent Green Martians.
- J'onn J'onnz, a Green Martian refugee of the planet, is typically one of the main members comprising the original Justice League roster, known as the Martian Manhunter.
- Mars is the name given to Ares by Romans.