Three companies based in Tysons are on a new list of the fastest-growing tech companies.

The companies, plus five others from Fairfax County, are included in Deloitte’s Technology Fast 500 list, which looks at the fastest-growing technology firms in North America. That’s according to the latest Fairfax County Economic Development Authority email newsletter.

The Tysons-based firms are:

• GTT Communications, a telecommunications infrastructure company
• KLDiscovery, which provides data-driven software and services to law firms, corporate legal departments and government agencies
• Digital Harbor, an enterprise software company focused on the healthcare industry

Other Fairfax County companies on the list are: LookingGlass Cyber Solutions of Reston (“leads local companies on the list with an 883 percent growth,” per FCEDA), GoCanvas of Reston, Research Innovations of Alexandria, Acero Health Technologies of Alexandria and ScienceLogic of Reston.