RIR may refer to:

• Regional Internet registry, nonprofit corporations that administer and register Internet Protocol (IP) address space and Autonomous Systems (AS)

Companies and organizations

• Richmond International Raceway

• Riverside International Raceway

• Romsdalshalvøya Interkommunale Renovasjonsselskap, a Norwegian waste management agency

British Army regiments:

• Royal Irish Rangers

• Royal Irish Rifles

Royal Irish Regiment, either:

• Royal Irish Regiment (1684–1922)

• Royal Irish Regiment (1992)

Media and entertainment

• Real Illusions: Reflections, an album by American guitarist Steve Vai

• Rock in Rio, a recurring music festival, originating in Rio de Janeiro, Brazil

• Rush in Rio, a live album by Canadian band Rush

Political parties

• React-Include-Recycle, a political party of Portugal

Other uses

• Rhode Island Red, a breed of chicken