"I'm very happy to be joining a traditional club in England," Stiepermann told Norwich's website. "I've seen the city here and it's very nice.
I didn't need a long time to think about it because I've known about Norwich City for a long time. It's good for me to play here. I know Marcel and Mario Vrancic and we spoke about the club, which was good."
Canaries boss Daniel Farke added: "Marco is an all-rounder and a creative guy. He started his career as a number ten but the last season played as a holding midfielder and in the left full-back position a lot.
"He will give us many options and is at a good age so that will help us to be more flexible."
Stiepermann, a former youth player at Borussia Dortmund, made 32 appearances for Bochum in the second tier of German football last season.