LGS
LGS may refer to:
Education
- Lahore Grammar School
- Lanark Grammar School
- Langley Grammar School
- Larne Grammar School
- Leeds Grammar School
- Leicester Grammar School
- Limavady Grammar School
- Loughborough Grammar School
Entertainment
- Looking Glass Studios, a defunct computer game company
- La Grande Sophie, a French singer-songwriter
Science
- Laser guide star, an adaptive optics instrument used in astronomy
- Latitudinal gradients in species diversity
- Leaky gut syndrome, an intestinal dysfunction
- LGS Innovations, a high-tech private company and former division of Bell Labs
- Lennox–Gastaut syndrome, a type of epilepsy
Software
- Liberty Steel Group, a British industrial and metals company