Covey Thomas Oliver, 93, a professor of international law who served in several diplomatic positions, including U.S. ambassador to Colombia, died Feb. 22 of chronic obstructive pulmonary disease at his home in Talbot County, Md., near Easton. He had a vacation home on Maryland's Eastern Shore since 1957 and, in recent years, also lived near Inverness, Calif.

Dr. Oliver was born in Laredo, Tex., and graduated in 1933 from the University of Texas and from the university's law school in 1936. Later that year, he began teaching at the University of Texas School of Law.

During World War II, he moved to Washington as a member of the U.S. Board of Economic Warfare, a federal body that procured raw materials and other items necessary for the war effort. He also served in Spain, where he was charged with purchasing industrial materials to keep them out of the hands of the enemies of the Allies.

Dr. Oliver served in the State Department until 1949, when he was appointed professor of international law at the University of California at Berkeley. He became the first director of the Institute of International Studies at Berkeley and was co-author of several books on international law.

While teaching at Berkeley, he was studying at Columbia University, from which he received a doctorate of juridical science in 1953.

In 1956, Dr. Oliver joined the faculty of the University of Pennsylvania Law School. He was named to the Inter-American Juridical Committee of the Organization of American States by President John F. Kennedy in 1962.

Two years later, Dr. Oliver, who spoke fluent Spanish and Portuguese, was named ambassador to Colombia, where he served for two years. In 1967, he became assistant secretary of State for Inter-American Affairs and was U.S. coordinator of the Alliance for Progress. He later held an executive position with the World Bank.

In 1969, Dr. Oliver returned to the University of Pennsylvania and taught until retiring in 1978. He briefly served as acting dean of the law school in 1978.

Dr. Oliver taught for three years at Rice University in Houston before holding a series of appointments as a visiting professor at several law schools, including American University.

He was president of the American Society of International Law and for many years was editor of the American Journal of International Law. He was a member of the Council of Foreign Relations, the American Law Institute, Phi Beta Kappa and the Order of the Coif.

Survivors include his wife of 60 years, Barbara Hauer Oliver of Easton; five children, Jane Oliver Menard of Baton Rouge, Lucy Oliver Sampson of Inverness, and Scotti L. Oliver, Woodlief H. Oliver and Jefferson T. Oliver, all of Talbot; a brother; and three grandchildren.