OIR may refer to:

• Organisation Internationale de Radiodiffusion (OIR); after 1960 Organisation Internationale de Radiodiffusion et de Télévision (OIRT).
• Organización Impulsora de Radio, the network division of Grupo Radio Centro.
• Operation Inherent Resolve a US DoD military operation against ISIL.
• Okushiri Airport—IATA code.
• Oxfordshire Ironstone Railway.

• Metam sodium
• Metamsodium
• Metamya
• Metamyiophasia
• Metamynodon planifrons
• Metamyobia
• Meta narrative
• Metanarsia
• Metanastria
• Metanema
• Metanema aurantiacaria
• Metanema cervinaria
• Metanema hirsutaria
• Metanema inatomaria
• Metanema quercivoraria
• Metanema vanusaria
• Metanephric adenoma
• Metanephrins
• Metanephroi
• Metang (Pokémon)
• Metano
• Metanoetics
• Metanoia (album)
• Metanoia (disambiguation)
• Metanoia (MGMT album)