Harold B. Hoskins, 81, former director of the State Department's Foreign Service Institute here, died Friday at New York Hospital in New York City.

An authority on the Middle East, he was a veteran of both World Wars. He had headed the Foreign Service Institute from 1955 to 1961.

Born in Beirut, Lebanon, of American missionary parents, Mr. Hoskins graduated from Princeton University, where he was elected to Phi Beta Kappa.

During World War I, he served with the 2d Division of the Marine Corps and received the French Croix de Guerre with Palm.

After the war, Mr. Hoskins became a businessman, working for several textile firms, including Cannon Mills.

In 1941, he was appointed acting assistant chief of the division of foreign activity correlation in the State Department. He served as a lieutenant colonel in the Army from 1942 to 1944, when he was named special assistant to the American ambassador in Tehran, Iran.

A year later, Mr. Hoskins became counselor for economic affairs at the American legation in Cairo and was assigned to diplomatic missions in Lebanon, Syria, Palestine, Iraq, Iran, Saudi Arabia and Ethiopia.

He resigned from the State Department at the end of 1945 and became a business consultant to various firms.

From 1951 until he was appointed head of the Foreign Service Institute, he was consultant to the assistant secretary of State for Near East and African Affairs.

Mr. Hoskins had been chairman of the board of trustees of the American University in Beirut, chairman of the board of Lingnan University in Canton, China, president of the board of the Near East College Association, and a former trustee of Smith College.

He is survived by his wife, Grania O'Malley Knott Hoskins, of the home in Stonington, Conn., and adaughter, Mrs. John W. Ackley III, of New York City.