Edwin Throckmorton Thacher (29 April 1896 – 21 March 1966) (commonly known as Ebby Thacher or Ebby T.) was an old drinking friend and later the sponsor of Alcoholics Anonymous co-founder Bill Wilson. He is credited with introducing Wilson to the initial principles that AA would soon develop, such as "one alcoholic talking to another," and the Jungian thesis which was passed along to Rowland Hazard and, in turn, to Thacher that alcoholics could recover by a "genuine conversion".