Middlesbrough 0 Norwich City 1: Boro's expensive strike force fails to fire as Canaries soar
Maddison, 20, netted a brilliant winner in the 12th minute to lift the Canaries level on points with the men from Teesside, just short of the play-off places.
Boro finished the game with £36m worth of striker talent on the pitch but could not find a way through Norwich's defence and goalkeeper.
The Canaries have now gone seven hours and 48 minutes without conceding under Daniel Farke, while Middlesbrough lost at home on a midweek night for the first time since 2011, halting a run of 28 matches.
Middlesbrough's attacking riches struggled to break down a Norwich defence who had not conceded in any of their previous four league games, a run which has seen them not lose since August.
In a bid to strengthen the home side's chances, manager Garry Monk recalled Adama Traore straight into his starting line-up after serving a three-match ban. There was also a place on the bench for £9m striker Martin Braithwaite after injury.
Norwich, who defeated their hosts when they played each other in the 2015 Championship play-off final at Wembley, arrived full of confidence and it showed. Their resilience to keep Middlesbrough at bay certainly highlighted recent improvements.
The only time Middlesbrough went close to scoring in the first half was when Britt Assombalonga's back-post header bounced across the face of the goal and was cleared after a decent run and delivery from winger Marvin Johnson.
The former Oxford wide-man and Traore seemed the likeliest source of supply but there was no cutting edge, so the defensive yellow shirts of Christoph Zimmermann and Timm Klose prevented Assombalonga from finding space.
It meant Norwich were able to stay ahead after that brilliant opening goal, even though it was gifted to them by Middlesbrough's Dael Fry.
The young defender, who has impressed so far this season, gave the ball away too cheaply on the left after a Norwich counter-attack. Marley Watkins rolled into the path of Maddison and he did the rest, striking his second goal for Norwich with a curling right-footed finish inside the top right corner from 25 yards.
The game opened up more in the second half. Norwich had the best of the early chances, when Darren Randolph had to make a fine stop at his near post to turn behind Cameron Jerome's effort after he had been put clear by Maddison.
There were half chances for Traore and Assombalonga as Middlesbrough - who introduced forward Ashley Fletcher for the defensively-minded Adam Clayton - stepped things up, but both efforts dropped nicely into the arms of goalkeeper Angus Gunn.
Assombalonga then had an even greater chance when he was afforded space to head freely at goal from Cyrus Christie's delivery, but once again it dropped into the arms of the keeper.
A couple of late penalty shouts were waved away too, as Norwich held on to return to Norfolk with an impressive three points.