9mm

9mm may refer to:
 * 9x18mm Makarov, a pistol cartridge. Commonly used in russian pistols and SMGs, such as the PM
 * 9x19mm Parabellum, a pistol cartridge. Commonly used in western pistols and SMGs, such as the MP5
 * 9x21mm Gyurza, a pistol cartridge. Commonly used in russian pistols and SMGs, such as the SR-1MP Gyurza
 * 9x39mm, a rifle cartridge. Commonly used in russian rifles, such as the AS VAL 9x39 special assault rifle