CIR or Cir may refer to:
Locations Christmas Island Resort, a casino/resort in the northeastern Indian Oceans CIR, FAA/IATA code for Cairo Regional Airport CIR, station code for the Caledonian Road & Barnsbury railway station in the UK
Organizations Center for Individual Rights, a US non-profit public interest law firm Center for Investigative Reporting, a nonprofit journalism organization Christian Initiative Romero, a German non-profit organization supporting industrial law and human rights in Central America Cosmetic Ingredient Review, a consumer safety group
Politics and government Commission on Industrial Relations, a US Congressional commission created in 1912 to study labor policy Commission Internationale de Ravitaillement, an inter-governmental body for coordinating purchases among Allies in World War I Commissioner of Internal Revenue, a US Treasury position Committee on International Relations, renamed the United States House Committee on Foreign Affairs in 2007 Comprehensive Immigration Reform Act of 2006, a US Senate bill Convention of Republican Institutions, a defunct French political party Cyber and Information Domain Service, the cyber branch of Germany's military (German: Cyber- und Informationsraum)
Science and medicine Carbon isotope ratio analysis, a subset of isotope ratio mass spectrometry Central ischaemic response, a cause of fainting Cir, abbreviation for the constellation Circinus CIR1, a gene that encodes the protein corepressor interacting with RBPJ in humans Corotating interaction region, the interface between fast and slow regions of the solar wind
Technology Carrier-to-interference ratio, in radio transmission Color infrared film, in photography Combustion Integrated Rack, an International Space Station microgravity research tool Committed information rate, or minimum guaranteed bitrate, in telecommunications Consumer IR, a class of remote control and communication devices
Other uses Campionato Italiano Rally (Italian Rally Championship), in automobile racing CIR, ICAO code for Arctic Circle Air, ICAO code CIR Group, an Italian holding company Committee on International Relations (University of Chicago), a graduate program Coordinator for International Relations, a position within the Japan Exchange and Teaching Program Cox–Ingersoll–Ross model, a model for interest rate dynamics