The Poland international, who joined the club's academy in 2006, has been ever-present this season as the Gunners sit top of the Premier League.
The 23-year-old, whose previous deal was due to expire in 2015, has now established himself as the club's first-choice shot-stopper after briefly losing his place in the side last season.
|7/2||Arsenal are 7/2 with BetVictor to win the Premier League|
“We’re very pleased Wojciech has signed a new long-term contract,” the Frenchman told the club's official website. “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 is thrilled to have extended his stay at the Emirates Stadium, having already been at the club for seven years, and is now targeting trophies as the Gunners bid to end their eight-year trophy drought.
“I am very pleased to have signed a new contract," said the Polish keeper. “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.”