IOB may stand for:
- Iranian oil bourse
- Indian Overseas Bank, a public sector bank in India.
- Input Output Banks, a term in Computer Science (hardware design)
- Input/Output Block, in FPGA
- Inside Outside Beginning, a file representation format for tagging tokens in chunking in computational linguistics
- Iyabo Obasanjo-Bello, a Nigerian politician
- Intelligence Oversight Board of the U.S. President's Foreign Intelligence Advisory Board
- Institute of Development Policy and Management, Instituut voor Ontwikkelingsbeleid en -beheer (University of Antwerp, Belgium).