RI
- Arterial resistivity index
- Chicago, Rock Island and Pacific Railroad
- Croatia
- IR (disambiguation)
- Indonesia
- Isaac ben Samuel
- Italian Radicals
- Lee (Korean surname)
- Li (unit)
- Raffles Institution
- Rapid intensification
- Referential integrity
- Refractive index
- Refugees International
- Rehabilitation International
- Reputation Institute
- Research institute
- Residual income
- Rex Imperator
- Rhode Island
- Rhombicosahedron
- Ri (administrative division)
- Ri (cuneiform)
- Ri (kana)
- Ri (prefix symbol)
- Ri (pronoun)
- Ri, Orne
- Rijeka
- Ring Indicator
- Riri (disambiguation)
- Ris (disambiguation)
- Rock Island District
- Rotary International
- Royal Institute of Painters in Water Colours
- Royal Institution
- Russia Insider
- Rí
- Solfege
- Tigerair Mandala