Gatwick handled 12.5 million passengers in the three months to June 30 with the help of a busy Easter and more Middle East flights.
The total represented a 1.7% year-on-year increase with long-haul leading the way.
Long-haul traffic was up by 2.2%, helped by increased frequency by Qatar Airways to Doha from June with up to three flights a day.
Tampa, Winnipeg, New York, Orlando and Buenos Aires led transatlantic growth.
Easter numbers were up by 2.5% over last year with Bilbao, Bodrum, Budapest, Mahon and Vienna the fastest growing destinations.
However, quarterly domestic traffic fell by 8.5%, Irish numbers were down marginally by 0.1% and European charter by 0.8%.
CEO Stewart Wingate said: “Gatwick is achieving robust growth in this spring/summer period where airport capacity is already well utilised.
“I’m proud even in these already busy spring/summer months we have been able to achieve yet further growth.
“Right across all airline types, carriers are starting new routes and increasing flight frequencies.”
He added: “In the near future, we will publish the final version of Gatwick’s masterplan, outlining potential options for future growth enabling the airport to make more of the world’s most exciting destinations accessible to more people than ever before while boosting trade and tourism opportunities locally and nationally.”