GDL may refer to:
- German Defence League
- GDL, the IATA airport code for Don Miguel Hidalgo y Costilla International Airport in Guadalajara, Mexico.
- Guadalajara, Mexico often referred just as "GDL" for its abbreviation.
- Godley railway station, England; National Rail station code GDL
- Grand Duchy of Lithuania
- GNU Data Language
- Geometric Description Language
- General-purpose Declarative Language
- Graph Description Language
- Graphite Description Language
- Game description language
- GNOME Developers Library
- The Graduate Diploma in Law, also known as the Common Professional Examination
- Gas diffusion layer, a component of a PEM fuel cell
- Gas dynamic laser
- Gewerkschaft Deutscher Lokomotivführer, a German trade union present in train companies
- Glucono delta-lactone, a natural food additive
- Graduated driver licensing, a system used for identifying different tiers of drivers used by some states in the United States
- Generalized Distributive Law, a general message passing algorithm