The Trust Territory of the Pacific Islands (TTPI) was a United Nations trust territory in Micronesia (western Pacific) administered by the United States from July 18, 1947, comprising the former South Pacific Mandate, a League of Nations Mandate administered by Japan and taken by the U.S. in 1944. On October 21, 1986, the U.S. ended its administration of the Marshall Islands district. The termination of U.S. administration of the Chuuk, Yap, Kosrae, Pohnpei, and the Mariana Islands districts of the TTPI soon followed on November 3, 1986. The UN only formally ended the trusteeship for the Chuuk, Yap, Kosrae, Pohnpei, Mariana Islands, and Marshall Islands districts on December 22, 1990. On May 25, 1994 the UN ended the trusteeship for the Palau district, after which the U.S. and Palau agreed to establish the latter's independence on October 1.

This area is now divided into four territories:

• The Republic of the Marshall Islands (RMI) was established in 1979 and signed a Compact of Free Association with the U.S. (effective October 21, 1986).
• The Federated States of Micronesia (FSM) was established in 1979 and signed a Compact of Free Association with the U.S. (effective November 3, 1986).
• The Commonwealth of the Northern Mariana Islands (CNMI) was set up in 1978 as a commonwealth in political union with the U.S.
• The Republic of Palau was established in 1981 and concluded a Compact of Free Association with the U.S. (effective October 1, 1994).