National Cathedral School (NCS) is an independent Episcopal private day school for girls in grades 4–12 located on the grounds of the Washington National Cathedral in Washington, D.C., United States.

Founded by philanthropist and suffragist Phoebe Apperson Hearst and Bishop Henry Yates Satterlee in 1900, NCS is the oldest of the institutions constituting the Protestant Episcopal Cathedral Foundation.

NCS has about 580 students in grades 4 through 12.

Its brother school, St. Albans, and the shared coeducational elementary school (K–3), Beauvoir,[1] are also located on the 57-acre (230,000 m2) Cathedral Close in Northwest Washington near the Washington National Cathedral.

Elinor Scully is the twelfth Head of School.