The Oahu Interscholastic Association (OIA) is an athletic conference composed of all public secondary schools on the island of Oahu, Hawaii, U.S.A. The OIA was first founded in 1940 as the Rural Oahu Interscholastic Association (ROIA). The five founding schools were Castle High School, Kahuku High School, Leilehua High School, Waialua High & Intermediate School and Waipahu High School. The OIA originally comprised all the rural schools on Oahu, which were all of the schools that were not situated in the main city of Honolulu. This changed however in 1970 with the addition of the five former public school members of the Interscholastic League of Honolulu – Farrington High School, Kaimuki High School, McKinley High School, Roosevelt High School and Kalani High School. After the public Honolulu schools joined, the league changed its identity from the ROIA to simply OIA to reflect the integration of all of the public high schools on the island.