OSL
- OSI (disambiguation)
- OSL Group
- Ongamenet Starleague
- Ontario Soccer League
- Open Shading Language
- Open Software License
- Open syllable lengthening
- Optically stimulated luminescence
- Orchestra of St. Luke's
- Order of Saint Luke
- Oregon Short Line Railroad
- Osl
- Oslo Airport, Gardermoen
- Oud-Strijders Legioen
- Outside Lands Music and Arts Festival
- Sosoliso Airlines