The 25-year-old Belgium captain, who has been hampered by injury since joining from Ajax in the summer of 2009, is understood to have agreed to stay at the Emirates Stadium until 2015.
“I am really happy to have signed a new contract with Arsenal. I always had the intention to stay here. I feel there is a big belief in me from the club, from the boss and from the fans and that is one of the reasons why I stayed,” said Vermaelen.
“Arsenal is a fantastic club. We have great supporters, we’re doing well financially and we are playing with some quality young players now and they will develop, which is very good for the future.”
Vermaelen scored eight goals in his first season before an Achilles injury suffered while away with Belgium sidelined him for the majority of last season, with further treatment meaning he has yet to figure during this campaign.
Manager Arsene Wenger added: “We are absolutely delighted that Thomas has signed a new long-term contract.
“Our plan is always to sign top-quality players and with Thomas extending his contract, we have done just that.
“Thomas is a special player, who has always made a huge contribution on the pitch and we are looking forward to him being a part of our future at Arsenal Football Club.”