IRB may refer to:
Organizations Immigration and Refugee Board of Canada, a Canadian administrative tribunal Indian Reserve Battalion, a special unit of the Indian Police Force (Ruđer Bošković Institute), a Croatian research institute Institutional review board, a committee to monitor research involving humans Instituto de Resseguros do Brasil, a Brazilian reinsurance company Instituto Ricardo Brennand, a museum in Recife, Brazil International Rugby Board, the former name of World Rugby, the governing board of rugby union IRB Infrastructure, an Indian road infrastructure company Irish Republican Brotherhood, an Irish secret revolutionary society of the 19th and early 20th centuries
Technology Interactive Ruby Shell, a shell for programming in Ruby ASEA IRB, a line of industrial robots
Other Ian Rank-Broadley, British sculptor and designer of the fourth coinage portrait of Elizabeth II Inflatable rescue boat, a rubber boat with an outboard motor used in surf lifesaving IRB racing Indian Rocks Beach, a city in Pinellas County, Florida Internal ratings-based approach (credit risk), a method for estimating bank capital requirements Internal Revenue Bulletin, a weekly publication of the U.S. Internal Revenue Service