A surface-to-surface missile (SSM) is a guided projectile launched from a hand-held, vehicle mounted, trailer mounted or fixed installation or from a ship. They are often powered by a rocket motor or sometimes fired by an explosive charge, since the launching platform is typically stationary or moving slowly. They usually have fins and/or wings for lift and stability, although hyper-velocity or short-ranged missiles may utilise body lift or fly a ballistic trajectory.

Surface-to-surface missiles are usually guided. An unguided surface-to-surface missile is usually referred to as a rocket (for example, an RPG-7 or M72 LAW is an anti-tank rocket whereas a BGM-71 TOW or AT-2 Swatter is an anti-tank guided missile).

Surface-to-surface missiles are usually broken down into a number of categories:

• ballistic missiles travel in a high trajectory, motor burns out partway through flight
  • tactical SSMs are usually short-range ballistic missiles (SRBMs), <1000 km (600 mi)
  • strategic SSMs are usually:
    • medium-range ballistic missiles (MRBMs), 1000-3000 km (600-2000 mi)
    • intermediate-range ballistic missiles (IRBMs), 3000-4800 km (2000-3000 mi)
    • long-range ballistic missiles (LRBMs), 4800-8000 km (3000-5000 mi)
    • intercontinental ballistic missiles (ICBMs), >8000 km (5000 mi)
• cruise missiles travel low to the ground, motor burns during entire flight, typical range 2500 km (1500 mi)
• anti-tank guided missiles travel low to the ground, may or may not burn motor throughout flight, typical range 5 km (3 mi)
• anti-ship missiles travel low over the ground and sea, often pop up or jink before striking ship, typical range 130 km (80 mi)

Please note that different parties break down missile type by the range differently. For example, the US DoD has no definition for LRBM and thus defines ICBM as those with a range greater than 5500 km (3500 mi). The International Institute for Strategic Studies don't define LRBM either, but their definition of SRBM is somewhat shorter than that of the US DoD. Figures above are thus representative but not definitive.