OAC or OAc may refer to:
Organizations Objectivist Academic Center, an educational institution founded by the Ayn Rand Institute Ocean Affairs Council, a government agency of Taiwan Ohio Arts Council Ohio Athletic Conference, an NCAA Division III athletic conference On Athletics Club, a professional group of long-distance runners One America Committee Online Archive of California Ontario Agricultural College Ontario Arts Council Orange Association Canada, the Canadian branch of the Orange Order Orthodox Anglican Church, a denomination of the Continuing Anglican movement in America, part of the Orthodox Anglican Communion Orthodox Anglican Communion, a worldwide Continuing Anglican body of which the Orthodox Anglican Church is a part
Other Acetoxy group (OAc), a chemical functional group Object Action Complex Oral anti-coagulant Ontario Academic Credit Amtrak station code for Oakland Coliseum Station Olivetolic acid cyclase, an enzyme