Still only 23, the Poland international has firmly established himself as Arsenal’s number one goalkeeper.
He has started each of the club’s 11 Premier League games this season and will now remain at the Emirates Stadium for a lengthy period, although the precise length of his new deal has not been disclosed.
Arsenal manager Arsene Wenger told the club's official website: "We're very pleased Wojciech has signed a new long-term contract.
"I have always believed he is an extremely talented player, with excellent reflexes and good mental strength.
"He continues to grow and improve all the time too, so he has the potential to be even better. He can be an important part of Arsenal Football Club for many years to come."
Szczesny, who joined the Arsenal academy in 2006 from hometown club Legia Warsaw, added: "I am very pleased to have signed a new contract. Arsenal is like my family and I'm so happy to be committing my long-term future here.
"I've been at this club for over seven years now and I'd just like to take the opportunity to thank everyone for their support towards me during my time here.
"I'm so proud to be an Arsenal player and am looking forward to helping our club towards success in the years to come."
