Dr. Francis Orlando Wilcox, 76, a vice chairman of the Atlantic Council of the United States and the former dean of Johns Hopkins University's School of Advanced International Studies in Washington, died Feb. 20 at Sibley Memorial Hospital after a heart attack.

Dr. Wilcox joined the Atlantic Council, a non-profit, non-partisan organization intended to strengthen ties between the United States and other North Atlantic Treaty Organization nations, in 1975. He was dean of the School of Advanced International Studies from 1961 to 1973 and before that had been an assistant secretary of State for international organizations and, earlier, chief of staff for the Senate Foreign Relations Committee.

As an assistant secretary of State, Dr. Wilcox served as a delegate to the annual assemblies of the United Nations and to meetings of such organizations as the World Health Organization.

He was born in Columbus Junction, Iowa, and graduated from the University of Iowa where he also earned a doctorate in political science. He taught at the universities of Iowa, Louisville, Michigan and Chicago before coming to Washington during World War II.

He worked in the Office of Coordination of Inter-American Affairs, the Office of Civil Defense, the Bureau of the Budget and the Library of Congress before 1947 when he became chief of staff of the Senate Foreign Relations committee.

Dr. Wilcox was the first person to hold that position after Congress authorized professional staffs for its committees, and his work included the committee's consideration of the Marshall Plan and the creation of NATO.

Dr. Wilcox remained with the Senate Foreign Relations Committee until 1955 when he became an assistant secretary of State. After retiring from Johns Hopkins in 1973 he became executive director of the congressionally created Commission on the Organization of the Government for the Conduct of Foreign Policy, and he remained in that job until the commission finished its work in 1975.

He was the author or co-author of a dozen books on international affairs and several magazine and periodical articles.

His first wife, the former Genevieve C. Byrnes, died in 1946. Survivors include his wife, Virginia, of Washington; a daughter by his first marriage, Mrs. John Millard of Great Falls; a son by his second marriage, Oliver, of Washington, and two granddaughters.