ALG may refer to:
- Algebra
- Algeria
- A-League, domestic football league in Australasia
- Algonquian languages, from its ISO 639 code
- American Laser Games
- Americans for Limited Government
- Anti-lymphocyte globulin, an immunosuppressive drug
- Application-level gateway
- Association of London Government
- Houari Boumedienne Airport, Algiers, Algeria, from its IATA airport code
- Advanced Landing Ground, tactical airfield created by the Allies in World War II
- Art. Lebedev Group, the holding company which owns Art. Lebedev Studio
- ALG (Advanced Landing Ground) Wormhout
- ALG Inc, a California source for automotive residual values.
- The F1 acronym of Jaime Alguersuari
- Application-level gateway