GLS can mean:
- Games, Learning, & Society Conference
- Gate-level simulation, used for a hardware design.
- General Lighting Service, a designation of an incandescent lamp standard
- General Logistics Systems, a logistics company
- Generalized least squares in the linear regression model
- The George Lopez Show
- Glaisdale railway station, England (National Rail station code GLS)
- Glasgow Literary Society, founded in 1753, a key institution of the Scottish Enlightenment
- Global Locating System, a generalized technique to geolocate remote assets. Used commercially by Skybitz
- Gloucestershire (GLS is the Chapman code for this English county)
- GNSS Landing System, in aviation, a precision approach system to an airport
- Government Legal Service, Legal Services for the UK Government and services
- Graeco-Latin square, a pair of orthogonal Latin squares
- Great Lake Swimmers, a Canadian indie folk band
- Guided Local Search, a search algorithm in computer science
- Guy L. Steele Jr., an American computer scientist
- Scholes International Airport at Galveston, IATA airport code
- Global Leadership Scholars, an undergraduate business honors program at University of Tennessee