William Griffith Wilson (26 November 1895–24 January 1971) (commonly known as Bill Wilson or Bill W.), was a co-founder of the society Alcoholics Anonymous. The other co-founder was Dr. Bob Smith. Bill's wife, Lois Wilson became the founder of Al-Anon, a group dedicated to helping the friends and relatives of alcoholics.

Wilson was born on 26 November 1895 in East Dorset, Vermont to Gilman Barrows Wilson and Emily Griffith. After a normal childhood, Wilson turned to heavy drinking during military service in WWI. In the 1920s Bill hung around Wall St. hauking stocks, although he never became a stock broker.

One day, an old drinking friend named Ebby Thatcher arranged a visit to the Wilson house. Expecting to spend a day drinking and re-living old times Wilson was instead shocked by Thatcher's refusal to drink. "I've got religion" he reportedly said to Wilson's surprise. Thatcher had recently joined a religious fellowship known as the Oxford Group. The Oxford Group helped alcoholics to stop drinking by performing various tasks such as making amends, acting as a witness to God's grace, admission of personal defeat, among others.

Wilson declined Thatcher's invitation to sobriety. However, later while under the influence of the hallucinogenic drug belladonna he claims to have had a "spiritual experience". His obsession to drink vanished at once. It is believed that Wilson connected his spontaneous release from alcoholism to the recent visit by Thatcher. This in turn inspired Wilson to seek out and bring the message of his recovery to others as Thatcher had done for him. Thatcher eventually returned to drinking.

Wilson joined the Oxford Movement, with a personal focus on helping alcoholic prospects. He had little success for the first six months of doing so. Then he made a trip to Akron, Ohio for a business deal. The transaction failed and in a state of frustration he was tempted to drink again. Instead he camped in a phone booth at the his hotel and dialed up clergy from a church directory. He had concluded his only hope to avoid drinking was to locate a fellow problem drinker to speak with, so he made these calls looking for one. This led him to a meeting with a local surgeon named Dr. Bob Smith who also had a drinking problem and was a member of the Oxford group. This would prove to be the start of Alcoholics Anonymous, and the date, June 10, 1935, is regarded as the date of origin for the fellowship.

In 1939, after no success in Akron and New York, Wilson decided to write a book that described their ideas of alcoholic recovery. In the fifth chapter, he explained "how it works" and documented the twelve steps on paper. The ideas of the steps were taken directly from the Oxford Group recovery techiques but tailored more specifically to alcoholics. After grappling for a proper title for the book, the title "Alcoholics Anonymous" was selected, and the new movement took the same name.

There was very little success with the book at first. Then in 1941 the Saturday Evening Post dispatched a reporter, Jack Anderson, to investigate this rumored group of alcoholics talking about a recovery plan. The resulting article proved to be the spark that ignited nationwide growth of the movement.

In the 1940s, Wilson learned about a long forgotten fellowship of reformed drunks that came into being in the 1800s. That fellowship was called The Washingtonians. The fact that a similar movement to A.A. had once existed, and faded into obscurity, had worrisome implications for the future of A.A. It is theorized that the Washingtonians fell apart because they lost focus by branching out beyond their initial scope of alcoholic recovery into various issues of the day. Fearful of a similar fate, among other reasons, Wilson began promoting the idea that a basic set of guidelines be established defining what A.A. was and was not. This resulted in the "Twelve Traditions" that complement the twelve steps. These traditions spell out A.A. as an organization that does not issue public opinions, support or oppose causes, impose membership requirements beyond a desire for sobriety, admonishes members to remain anonymous at the public level and so on.

Wilson refused numerous honors during his life, including an honorary degree from Yale University, and refused to allow himself to be on the covers of magazines. Before the twelve traditions were in place, Wilson was not shy about personal publicity. He later became an anonymous member and would later state that the principle of "public anonymity" was the greatest "spiritual principle" advanced by A.A.

Wilson suffered long bouts of depression before and after sobriety and engaged in psychiatric therapy. At Trabuco College in California, he became friends with Aldous Huxley and Gerald Heard, the founder of the College. In the 1950s, Wilson and Heard experimented with LSD, a potent psychedelic theorized to have the potential to help alcoholics and drug addicts stop their cycles of abuse. These claims about LSD's usefulness have been disputed, and, due to the fact that LSD was scheduled by the DEA on October 27, 1970, as a Schedule I drug, they have not been investigated further.

A lifelong smoker , Wilson died of emphysema and pneumonia on 24 January 1971 in Miami, Florida.

The phrase "Friends of Bill W." is sometimes a code for Alcoholics Anonymous.

Bill Wilson's story and his eventual founding of AA was dramatized in the 1989 TV movie My Name is Bill W., starring James Woods and James Garner.

Time magazine named Wilson to their "Time 100" list of "The Most Important People of the 20th Century.