Allyson Kay Duncan is a former United States circuit judge of the United States Court of Appeals for the Fourth Circuit. She was the Fourth Circuit's first female African American judge.

The United States Court of Appeals for the Fourth Circuit is a federal court located in Richmond, Virginia, with appellate jurisdiction over the district courts in the following districts:District of Maryland Eastern District of North Carolina Middle District of North Carolina Western District of North Carolina District of South Carolina Eastern District of Virginia Western District of Virginia Northern District of West Virginia Southern District of West Virginia