Benjamin Cushing Duniway (1907–1986) was an American federal judge.
Duniway graduated from Stanford Law School in 1931 and was a Rhodes scholar in 1933. He practiced law in San Francisco for the next 26 years, except for the years 1942–1947 spent with the Federal Office of Price Administration. He was considered for a federal judgeship during the Truman administration. In 1959, Governor Pat Brown named Duniway to the California First District Court of Appeal in San Francisco.
Duniway was appointed to the Ninth Circuit Court of Appeals by President John F. Kennedy in 1961. He took senior status in 1976, and Procter Hug was appointed to the vacant seat. He remained on the bench as senior judge until his death in 1986.
He authored the circuit court's majority opinion for Oliphant v. Suquamish Indian Tribe, upholding an American Indian tribal court's criminal jurisdiction over non-Indians on tribal land. That decision was eventually reversed by the Rehnquist Court.
Duniway was the grandson of Abigail Scott Duniway, an Oregon pioneer and noted women's rights advocate.