Petrus Tun (19 March 1936 – 23 March 1999) was a Micronesian politician, who played an important role during the first days of Micronesian independence and in the Trust Territory times that preceded them. Tun was elected to the Senate of Micronesian Congress from Yap district. He was instrumental in negotiating the first Compact of Free Association between the FSM and the United States and later served as the first Vice President of the Federated States of Micronesia during the first term of President Tosiwo Nakayama (1979–1983).