First half goals from Imrân Louza and Keinan Davis secured Slaven Bilić's first win at Vicarage Road as Watford manager.
Louza made up for an early penalty miss by volleying his side in front from an Ismäila Sarr cross before Davis made it two after some more excellent wing play by Sarr.
Josh Sargent pulled one back for Norwich on the stroke of half time but the hosts stayed resolute in the second half to secure the three points.
Bilić made three changes from the side which lost 3-1 to Blackpool at Bloomfield Road. Davis, Yáser Asprilla and Craig Cathcart were recalled to the team whilst João Pedro was deemed fit enough to make the substitutes bench.
Both sides came into the game off the back of defeats, with Norwich succumbing to a 3-2 defeat at home to Preston last time out. They knew that a win tonight, though, would take them to the top of the Championship.
The hosts started the game at a ferocious pace, with Louza setting up Davis in the opening minutes only to be denied by a great save by Norwich goalkeeper Angus Gunn.
After just ten minutes the Hornets were gifted a golden opportunity to get themselves in front when Sarr was brought down in the box. Louza stepped up to take the penalty but was denied by Gunn who guessed the right way and got down well to save.
Five minutes later, the Moroccan international made up for his penalty miss by putting Watford in front. Sarr's cross from the left was met by an unmarked Louza who got the better of Gunn this time by volleying the ball into the ground and past the stationary keeper.
Chances for the visitors were hard to come by in the first half but they came close when Max Aarons fizzed a shot just wide of the post after Daniel Bachmann had beat away a Kieran Dowell strike from range.
It hasn't been the easiest start to life as Watford manager for Bilić, but his side were playing with confidence and before long found themselves two goals to the good.
Sarr teed up Asprilla in the box following a majestic dazzling run and the young Columbian prodded the ball to Davis who had enough time to control the ball and steady himself before coolly slotting the ball past Gunn.
It looked like Watford were going to comfortably see out the half with their two goal advantage intact before Sargent fired Norwich back into the game on the stroke of half time.
The American cut in from the left hand side and rifled a shot past Bachmann at his near post. The hosts had been well in control of much of the first half so would have been disappointed to let the Canaries back into the game so close to the half time whistle.
Dean Smith's men started the second half in a much more energetic fashion. They had the ball in the back of the net five minutes after the restart when Sargent thought he had grabbed his second goal of the evening, only for it to be ruled out for offside on Pukki.
They continued to push for an equaliser and captain Grant Hanley rattled the bar from a corner after Kenny McLean's flick had been deflected past the post.
Watford seemed to be getting deeper and deeper as Norwich exerted more pressure, but the introduction of João Pedro from the bench swung the game back in their favour. The Brazilian was excellent and constantly got on the ball to push his side further up the pitch.
Norwich seemed to peter out and in the end it was comfortable for Watford to see the game out and grab Bilić's first win at Vicarage Road.