The Association of Field Ornithologists (AFO) is one of the world's major societies of professional and amateur ornithologists dedicated to the scientific study and dissemination of information about birds in their natural habitats. Founded in 1922 as the New England Bird Banding Association, AFO shortly thereafter became the Northeastern Bird-Banding Association. This origin promoted an emphasis on bird banding and field techniques, always with field studies as a focus. Field studies continue to be a focus and, with the new techniques in molecular ecology, bioacoustics technology, and behavioral ecology now available, field studies of birds are approaching ever new questions. AFO encourages the participation of amateurs in research, and emphasizes the conservation biology of birds.

The AFO publishes the Journal of Field Ornithology and prides itself as serving as a bridge between the professional and the amateur ornithologist. The organization's membership and governing council consist of both amateur and professional ornithologists, in recognition of the contributions that both make to ornithology.