The soldier was killed as a result of small arms fire that happened in the Sangin area, in central Helmand Province, during the evening of 20 December 2009.
Spokesman for Task Force Helmand, Lieutenant Colonel David Wakefield, said:
"It is my sad duty to inform you that a soldier from The Royal Military Police was shot and killed last night in the Sangin area of Helmand Province. A Royal Military Policeman who died in the line of his duty, and who we will remember."
Next of kin have been informed and have asked for a period of grace before further details are released.
There is a possibility that this incident was caused as a result of friendly fire.
The incident is being investigated in Afghanistan but no firm conclusion will be reached until after the coroner's inquest. The MOD will not release any further information until the coroner's inquest concludes in due course.