Arthur Thomas Tienken (August 5, 1922 Yonkers, New York - May 7, 2006, Arlington, Virginia) was an American career Foreign Service Officer who held ambassadorships to Gabon and São Tomé and Príncipe (1978-1981).
Tienken graduated from Princeton University, earning a bachelor's in 1946 (political science) and a master's in international relations at the Woodrow Wilson School of Public and International Affairs in 1950. Tienken entered with the Class of ‘44 but took time off from his studies, serving as a first lieutenant in the 3094th Quartermaster Company of the Western Pacific in the Philippines during World War II.
His first position in the Foreign Service, in 1950, was as a Kreis resident officer, or district governor, in Germany. He served in various the Belgian Congo, Mozambique, Zambia, Tuniasia and Ethiopia. He then spent four years at the embassy in Brussels. Upon his return stateside, he attended the Naval War College in Newport, Rhode Island and was a diplomat-in-residence at Marquette University. He retired in 1987.
Tienken died of stomach cancer at his home.