The soldier was killed as a result of an explosion that happened near Forward Operating Base Zeebrugge in the Kajaki area of Helmand province this morning.
Spokesman for Task Force Helmand, Lieutenant Colonel David Wakefield, said:
"It is with deep sadness I must inform you that a British soldier, one of our comrades, was killed this morning by an explosion in the Kajaki area of northern Helmand.
"He was from 3 RIFLES and was on a foot patrol against insurgents to the north east of Forward Operating Base Zeebrugge, an area known by us as 3 Peaks, when the explosion happened.
"His courage and resolve, confronting the enemy and the dangers of IEDs day-on-day, will not be forgotten; we will remember him."
Next of kin have been informed and have asked for a period of grace before further details are released.