The new destinations are Clermont, Cologne, Deauville, Edinburgh, Glasgow and Ponta Delgada (in the Azores).
The airline has said it will also offer more flights and improved schedules on 40 other routes this year, including Edinburgh and Glasgow, where services will increase from three to four times a day by winter 2015 in response to "phenomenal demand" from business customers.
The new services take the number of routes Ryanair offers up to 130 in total, more than British Airways offers from Heathrow.
"Ryanair is pleased to launch six new London Stansted routes – to Clermont, Cologne, Deauville, Edinburgh, Glasgow International and Ponta Delgada (Azores) – as well as increased frequencies on 40 other routes. UK visitors and customers can choose from a total of 130 exciting Stansted summer routes, which will deliver over 17m customers p.a. at London Stansted, as we grow by 12%," said Ryanair chief executive Michael O’Leary.
Earlier in the week, the airline announced a new route from Glasgow International to Berlin.