Dickson moved to Northampton from Newcastle in the summer of 2008 and has won the Amlin Challenge Cup and the LV= Cup at his time at the club.
He has made 88 appearances for the Saints, including 21 in Europe.
"It's a great club to be at," Dickson said.
"The squad and players are brilliant and it's been the best move I've ever made in my career. I'm lucky to be a part of a club that's going places and it's been really enjoyable to be a part of something that is getting better every season. I love playing in front of the Saints fans as well, who whether we win or lose always get behind us.
"This season has been a bit frustrating for me. I like watching rugby, but not when I'm injured and want to be out there, and I'm really appreciating every game that I play.
"I haven't been surprised by how far we've come in the past three years. A special group of guys have been brought together at Franklin's Gardens, and we're growing together all the time. Jim, Dorian and Paul are also really ambitious coaches and want to win every game going.
"That's what I'm about and what the club's about, too."
Director of rugby Jim Mallinder says that Dickson's new contract is a statement of intent for both the player and the club.
"Over the last three years Lee has shown time and again how important he is to the team and I'm delighted that he has decided to sign a new contract, especially as he still had time to run on his last one," Mallinder commented. "Lee plays at a consistently high level and demands the best from both himself and the rest of the players around him.
"From the coaches' point of view it is important that we are keeping our core group of players together. It takes time to build a team that can compete at the top end of the Premiership and in the later stages of the Heineken Cup on a regular basis. We now have a group of players who have been together for a few years already but who are still young enough to keep developing and growing as a team."