Philippine Airlines will become the 16th member of the Oneworld alliance.
The carrier signed a memorandum of understanding with the Oneworld governing board on June 6 in Rio de Janeiro, where the IATA Annual General Meeting is taking place.
The process of joining an airline alliance can take take several months or more than a year.
Philippine Airlines serves 69 destinations -- 31 that aren't served by another Oneworld member. It flies to six U.S. cities from Manila: Seattle, San Francisco, Chicago, Los Angeles, New York and Honolulu. It also flies from Manila to the U.S. territory of Guam.
Among the more prominent Oneworld members are American, Alaska/Hawaiian, British Airways, Qantas, Qatar, Japan Airlines, Iberia, Finnair and Cathy Pacific.
American Airlines CEO and Oneworld chairman Robert Isom said adding Philippine Airlines would "strengthen our connectivity across key markets in the Asia Pacific region."