1920 U.S. National Championships – Women's singles

Molla Mallory defeated Marion Zinderstein 6–3, 6–1 in the final to win the women's singles tennis title at the 1920 U.S. National Championships. The event was played on outdoor grass courts and held at the Philadelphia Cricket Club in Chestnut Hill, Philadelphia from September 20 through September 25, 1920. It was Mallory's fifth U.S. National singles title.