The Wilson Ornithological Society (WOS) is an ornithological organization that was formally established in 1886 as the Wilson Ornithological Chapter of the Agassiz Association. It is based at the Museum of Zoology, University of Michigan, Ann Arbor, USA. It was named after Alexander Wilson, a prominent early American ornithologist. The name of the group later evolved through being generally known as the Wilson Ornithological Club (or just the Wilson Club) until it became the WOS in 1955. It publishes the Wilson Journal of Ornithology (previously the Wilson Bulletin). It is a member of the Ornithological Council.