IRN

IRN may refer to:


 * Input-referred noise
 * Independent Radio News, a news service to commercial radio stations in the United Kingdom
 * Independent Radio News (New Zealand), not affiliated with the United Kingdom company above
 * International Rivers Network, a non-profit environmental organization based in California, United States
 * Imperial Russian Navy, the navy of the Russian Empire
 * Iran (ISO 3166-1 alpha-3 country code)
 * Indian-ringnecked parakeet (abbreviated IRN), the subspecies Psittacula krameri manillensis of the rose-ringed parakeet
 * Islamic Council Norway, Islamsk Råd Norge
 * Italian Royal Navy, the navy of the Kingdom of Italy