MK or mk may refer to:
The Mk 14 Enhanced Battle Rifle (EBR) is an American selective fire military designated marksman rifle chambered for the 7.62×51mm NATO cartridge.
The Mk 19 grenade launcher (pronounced Mark 19) is an American 40 mm belt-fed automatic grenade launcher that was first developed during the Vietnam War.
MKE Ankaragücü or fully Makina Kimya Endüstrisi Ankaragücü (Turkish pronunciation: [ˈɑŋkɑɾɑɡʲyd͡ʒy]), is a professional Turkish sports club located in the city of Ankara, Turkey.
The Mk44 Bushmaster II is a 30 mm chain gun manufactured by Alliant Techsystems. It is a derivative of the 25 mm M242 Bushmaster, and uses 70% of the same parts as the M242 while increasing the firepower by as much as 50% with the 20% increase in caliber size.
The United States Navy Mark 12 Mod 0/1 Special Purpose Rifle (SPR) is a semi-automatic rifle in service with United States Special Operations Forces used in the designated marksman role.