Pegasus will operate up to 55 direct flights to Turkey a week this summer, flying to five destinations – Ankara, Antalya, Dalaman, Istanbul and Izmir.
After launching from Stansted in 2007 with a single Istanbul flight, Pegasus has now carried six million passengers on routes from Stansted.
Gareth Powell, Stansted managing director, said Pegasus had built "an incredibly popular network" at the Essex airport.
"By increasing capacity and frequency on existing routes, passengers will have more choice and flexibility without having to travel to other airports," said Powell.
