It will initially be open daily to NHS staff and invited key workers from Wednesday (8 April) between the hours of 9am and 5pm on an appointment-only basis.
Gatwick chief executive Stewart Wingate said: "We are pleased to support the national effort against the spread of the coronavirus by allowing Gatwick facilities to be used as a vital testing centre for frontline health workers.
"We have the space available at Gatwick to be able to host such a large-scale operation. Alongside keeping the airport open to support repatriation flights, amongst others, we are happy to be able to support the NHS, government and the country in whatever way we can."
Health minister Lord Bethell added: "This new service will help end the uncertainty of whether NHS and social care staff need to stay at home meaning those who test negative will be able to return to work.
"This is a national effort, and we are proud to be working with a number of partners to turn this ambition into a reality and roll out additional capacity to where it is needed.”
It comes after British Airways last week announced it was suspending its operations at Gatwick, which has shut its North Terminal and consolidated operations in its South Terminal.
The North Terminal will be initially closed for a month, with the closure kept under regular review. A decision on reopening the terminal will depend on airline traffic and government public health advice, said Gatwick.
