Johnson has been a regular in the heart of the Canaries' midfield this season, making 27 appearances in all competitions with his performances leading to a new deal. The 25-year-old joined the club in 2011 on a free transfer after his contract at Championship side Leeds expired.
"I'm absolutely delighted. As soon as I heard that the club wanted to sit down and sort a new deal I just wanted to get it done and I'm delighted that it has," he told the club's official website.
"I think I'm playing the best football of my career and I'm playing in the best league in the world. I think this is a club that is moving forward and I want to be a part of that.
"We've proved that we're good enough to be here and we know how hard it is to stay in this league, but we work as hard as we can to do exactly that."
Manager Chris Hughton hailed the performances of Johnson, who has so far made a total of 57 appearances for the Barclays Premier League outfit.
"I'm absolutely delighted we have secured the services of Bradley Johnson," he said.
"He has been a tremendously consistent performer for us in midfield not just this season, but since he joined the club from Leeds United."