{{Disambiguation}}
'''Mk3, MkIII''' and '''Mark 3''' also redirect here.
'''Mark III''' may refer to:
[[File:MkIIIA1 MkIIIA2 Offensive grenade.JPG|thumb|right|MkIIIA2 grenade]]
[[File:Ruger Mark III.jpg|thumb|right|Ruger Mark III]]
* The [[MkIIIA2]], a high-explosive/fragmentation hand grenade
* The [[Ruger Mark III]], a [[.22 Long Rifle]] pistol