AGS
- AGS (motorcycle manufacturer)
- AGS Airports
- AGS Entertainment
- AGS-17
- AGS-30
- Aberdeen Grammar School
- Acklam Grange School
- Adams' Grammar School
- Adrenogenital syndrome
- Advanced Gun System
- Adventure Game Studio
- Aggies (disambiguation)
- Aicardi–Goutières syndrome
- Airborne Ground Surveillance
- Alabama Great Southern Railroad
- Alaqsite'w Gitpu School
- Alberta Geological Survey
- Alcester Grammar School
- Alliance Graduate School
- Alliance Ground Surveillance
- Alpha Gamma Sigma (fraternity)
- Alpha Gamma Sigma (honor society)
- Alpha-gal syndrome
- Alternating Gradient Synchrotron
- American Gem Society
- American Geographical Society
- American Geriatrics Society
- American Graduate School in Paris
- American Graduate School of International Relations and Diplomacy
- Annualized Geothermal Solar
- Antrim Grammar School
- Apollo Abort Guidance System
- Argyle Street railway station
- Arkansas Governor's School
- Armored Gun System
- Atlantic Geoscience Society
- Auckland Grammar School
- Augusta Regional Airport
- Australian Government Solicitor
- Automobiles Gonfaronnaises Sportives
- Aylesbury Grammar School
- County Antrim
- Esimbi language
- Game Boy Advance SP
- Garda Síochána
- Government simulation game
- Grass sickness
- List of auxiliaries of the United States Navy
- M8 Armored Gun System
- Silver sulfide