Van Wolfswinkel, 25, endured a difficult first season at Carrow Road after becoming Norwich's record signing following an £8.5 million ($13.3 million, 10 million euro) move from Sporting Lisbon a year ago.
He scored just once in 27 appearances as the Canaries were relegated to the second tier after a three-year stint in the Premier League.
However, Saint-Etienne boss Christophe Galtier hopes a change of scenery can help Van Wolfswinkel rediscover the form that saw him net 45 goals in two seasons with Sporting.
"Ricky was someone we had followed and identified but we didn't think we would have the chance to get him on loan. He's a player Saint-Etienne cannot afford to buy," said Galtier, although the agreement does include an option to make the switch permanent.
"When they spoke to me about getting a loan due to Norwich's relegation to the English second division, there quickly became some good exchanges between us and his advisers.
"He's a boy that seems quickly at ease, I don't think there will be any problems integrating him into the squad or for him to adapt," added Galtier, whose side begin the 2014-15 Ligue 1 season away to Guingamp on Saturday.
Van Wolfswinkel, capped twice by the Netherlands, is Saint-Etienne's second close-season signing following the arrival of Kevin Monnet-Paquet from Lorient.
- Sports & Recreation
- Ricky Van Wolfswinkel
- Christophe Galtier
- Norwich City