A submarine-launched cruise missile (SLCM) is a cruise missile that is launched from a submarine. Current versions are typically standoff weapons known as land-attack cruise missiles (LACMs), which are used to attack predetermined land targets with conventional or nuclear payloads. Anti-ship cruise missiles (ASCMs) are also used, and some submarine-launched cruise missiles have variants for both functions.

A ballistic missile submarine is a submarine capable of deploying submarine-launched ballistic missiles (SLBMs) with nuclear warheads. These submarines became a major weapon system in the Cold War because of their nuclear deterrence capability. They can fire missiles thousands of kilometers from their targets, and acoustic quieting makes them difficult to detect, thus making them a survivable deterrent in the event of a first strike and a key element of the mutual assured destruction policy of nuclear deterrence. The deployment of ballistic missile submarines is dominated by the United States and Russia. Smaller numbers are in service with France, the United Kingdom, China and India; North Korea is also suspected to have an experimental submarine that is diesel-electric powered.