Mars Two, Mars II, Mars 2 or variant, may refer to:
- Mars II (Deimos), the second moon of Mars
- Mars 2, the Soviet spaceprobe for Mars
- HMS Mars (1746), the second ship named HMS Mars
- USS Mars (AC-6), the second ship named USS Mars
- the second volume of Fuyumi Soryo's Mars (manga)
- MARS II / LRU / MLRS-I, a European variant of the M270 Multiple Launch Rocket System