IDB can mean:
- Inter-American Development Bank, also known as IADB
- Islamic Development Bank, a multilateral development financing institution also known as ISDB
- Israel Discount Bank, an Israeli bank with branches in the United States as well as in Israel.
- IDB Communications Group, Inc., a constituent of MCI Inc.
- Illegal Diamond Buying, the term used at the turn of the 19th-20th century for diamond trading outside the De Beers cartel.
- Industrial Development Bank, now the Business Development Bank of Canada
- Intel debugger, a proprietary debugger
- Intelligent drum and bass, a subgenre of drum and bass music
- Internal drainage board, a type of English and Welsh water level management authority
- Interface Descriptor Block, a Cisco IOS internal data structure that contains information on network data
- Identity by descent (biology), alleles that are identical because they descended directly from the same ancestral allele.
- Irish Dairy Board