The abbreviation IOR may refer to:

• Importer of record, term in import and export
• inclusive or - as opposed to XOR (exclusive OR)
• Independent Order of Rechabites
• Index of refraction
• India Office Records
• Indian Ocean Region
• Indian Ocean Rim, e.g. as in Indian Ocean Rim Association
• Inhibition of return, a phenomenon in visual perception
• Interleaved or Random, a computer benchmark for I/O
• International Offshore Rule, an early handicapping system for yacht racing
• Interoperable Object Reference, a reference to a CORBA or RMI-IIOP object
• Institute of Refrigeration, a UK scientific charity and membership organisation
• Institute of Recruiters, a non-profit Institute for recruiters and HR professionals
• Istituto per le Opere di Religione (Institute for Religious Works), the "Vatican Bank"
• Interest on Reserves, a term used in macroeconomics having to do with reserves placed at the central bank
• IORgroup Ltd (formerly Interiors of Richmond), a London-based commercial interior design company
• I.O.R., optics company of Romania
• IOR (formerly Inland Oil Refiners) is the company that owns and operates the Eromanga Refinery in outback Queensland, Australia
• IOR, IATA airport code for Inishmore Aerodrome