LSG can refer to:
- LSG (band), an R&B group
- L.S.G., a Techno-Trance project by Oliver Lieb
- LSG Sky Chefs, an airline catering company
- Laparoscopic Sleeve Gastrectomy, a surgical weight-loss procedure
- League of Saint George, a far right group
- Loss of Strength Gradient, used in the context of military might; a theory that strength declines as distance increases
- Louisiana State Guard, the state defense force of Louisiana
- Virgo Supercluster, the Local Supercluster of galaxies
- Landing Ship Gantry a US Navy World war 2 type ship