William Andreas Brown (born September 7, 1930) served as the U.S. Ambassador to Thailand from 1985 to 1988 and U.S. Ambassador to Israel from 1988 to 1992. He also served as the last Chief of mission (Chargé d'affaires) of the U.S. Embassy to the Republic of China (ROC) stationed in Taipei, Taiwan after the departure of Ambassador Leonard S. Unger in 1979. After diplomatic ties between Taipei and Washington severed, he remained on the island to set up the Taipei Main Office of the American Institute in Taiwan (AIT) at the former compound of U.S. Military Assistance Advisory Group (MAAG). He then served as the AIT's acting Director and deputy director (after the inauguration of Charles T. Cross, first AIT Director in Taipei).