Elias Kachunga netted both goals to earn Huddersfield their first Carrow Road success in 47 years.
The former German Under-21 international, on loan from Bundesliga strugglers Ingolstadt, took his tally for the season to nine.
But he should have been celebrating a hat-trick against the hapless Canaries, whose defending was almost comical at times.
Skipper Jonny Howson was Norwich’s marksman with his first goal since returning from a nine-game absence through injury.