GLK may refer to:
- Gilaki language (ISO 639-3 code "glk")
- Glk (software), a portable API created by Andrew Plotkin.
- Mercedes-Benz GLK-Class, a German sport utility vehicle
- Glucokinase, an enzyme that facilitates the phosphorylation of glucose into glucose 6-phosphate.
- Gay and Lesbian Kingdom of the Coral Sea Islands