Plasma cannon may refer to:
- Plasma weapon, a type of directed-energy weapon that fires a beam, bolt, or stream of plasma
- Plasma railgun, a linear accelerator which uses two long parallel electrodes to accelerate a "sliding short" armature
- MARAUDER, a United States Air Force Research Laboratory project concerning the development of a coaxial plasma railgun
- Plasma-powered cannon, an experimental weapon which accelerates a projectile by means of a plasma discharge between electrodes at the rear of the barrel