Thelma Cornelia Davidson Adair was an American educator, Presbyterian church leader, advocate for human rights, peace and justice issues, writer and activist. She was active with Church Women United, a Christian women's advocacy movement. Davidson Adair was an ordained Elder for the Mount Morris Ascension Presbyterian Church of New York City in Harlem. Adair was the moderator for the 1976 Assembly United Presbyterian Church in the United States of America (UPCUSA). She married, in 1940, the Reverend Arthur Eugene Adair, founder and minister of the church from 1943 until his death in 1979.