Castle of Oia

Oia, Spain, a municipality in Galicia, in the province of Pontevedra Oia, Greece, a small town on the island of Santorini Oia, alternate name of Oea (Attica), a town of ancient Attica Oia, alternate name of Oea (Thera), a town of ancient Thera (Santorini)

Ourilândia do Norte Airport, an airport with IATA identifier OIA Orlando International Airport ("OIA" is a local abbreviation), which actually uses the letters MCO for its airport designation

Office of the Independent Adjudicator, the higher-education ombudsman in the United Kingdom Official Information Act 1982, a piece of New Zealand legislation Office of Insular Affairs, an office of the United States Department of the Interior DHS Office of Intelligence and Analysis, an office of the United States Department of Homeland Security Office of Intelligence and Analysis (United States Department of the Treasury), the intelligence organization of the U.S. Department of the Treasury Oman Investment Authority, a sovereign wealth fund