IG
- Air Italy (2018–2020)
- IG Farben
- IG Group
- IG postcode area
- Ig Nobel Prize
- Ig, Slovenia
- Igbo language
- Immunoglobulin
- Imperial Guard (Warhammer 40,000)
- Imperial gallon
- Imperium Galactica
- Impressions Games
- Indigo Girls
- Information governance
- Inscriptiones Graecae
- Insomniac Games
- Inspector General
- Inspector General of Prisons
- Inspector-general of police
- Insulated glazing
- Integrated graphics
- Interim Government of Ambazonia
- Internet Group
- Investment grade bond
- Invictus Games
- Invictus Games (company)
- Invictus Gaming
- Irish Guards
- Island Games
- Italian Greyhound
- Justice Guild of America
- Production I.G
- Star Wars