Caseless ammunition is a type of small arms ammunition that eliminates the cartridge case that typically holds the primer, propellant, and projectile together as a unit.

Caseless ammunition is an attempt to reduce the weight and cost of ammunition by dispensing with the case, which is typically precision made of brass or steel, as well as to simplify the operation of repeating firearms by eliminating the need to extract and eject the empty case after firing. Its acceptance has been hampered by problems with production expenses, heat sensitivity, sealing, and fragility. Its use to date has been limited to prototypes and low-powered firearms.