Linda Norgrove, 36, died during an attempt to free her from the armed militant group who kidnapped her on September 26, the Foreign Office announced on Saturday.
She was killed on Friday night during a rescue operation, thought to have been carried out by US special forces working alongside Afghan troops.
Full details of the rescue operation have yet to be released.
The Foreign Secretary William Hague said: “It is with deep sadness that I must confirm that Linda Norgrove, the British aid worker who had been held hostage in eastern Afghanistan since 26 September, was killed at the hands of her captors in the course of a rescue attempt last night.