The 24-year-old is currently recovering from a serious knee injury, sustained on the opening day of the season against Everton.
Bennett, who signed from Brighton in 2011 and has made 64 appearances, scoring three goals, for City, said on canaries.co.uk: "I'm delighted. Obviously I wasn't expecting it being injured, but it's fantastic.
"It's been a great two years so far and what we've achieved in that time has been absolutely brilliant."
Manager Chris Hughton said: "We're really delighted for Elliott and he thoroughly deserves it.
"He's going through a big chunk of the season injured, so it just shows that we have that faith in him. He's such a good individual, so we feel he'll be fine coming through."