"I accept this honor on behalf of those who have sacrificed so much for our two countries, and I thank Her Majesty the Queen for her steadfast support for those who continue to serve and their families," Dempsey said in a statement.
Non-British nationals can be awarded a knighthood, but they are not given the honorific "Sir."
British officials said the honorary knighthood was in recognition of Dempsey's "steadfast" commitment to defense cooperation between Britain and the United States.
The two countries have tightly interlinked militaries and have operated closely for decades.
An Irish-American who taught English literature to cadets at West Point, Dempsey graduated from the same class at the military academy as another four-star general, David Petraeus.
Dempsey, 64, is well-known in the US military for his extroverted personality, irreverent sense of humor and a penchant for singing in public.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)
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