Canaries boss Chris Hughton had been keen to bring in the former Everton man to provide needed cover for injured centre-half Michael Turner.
The Barclays Premier League club posted on Twitter on Thursday evening: "#NCFC can confirm the loan signing of Joseph Yobo from Fenerbahce until the end of the season, subject to governing body approval."
The 33-year-old Nigeria international joined the Istanbul outfit in summer 2010, initially on loan, having played for Everton since 2002.
Hughton, who has also brought in midfielder Jonas Gutierrez on loan from Newcastle this month, earlier said: "Joseph knows this division very well and has great experience, so let's hope that one can be completed."
Fener also confirmed the deal on their website, with a statement which read: "Our player, Joseph Yobo, as a result of an agreement between the two clubs, will spend the rest of the season in the Premier League with Norwich City.
"Yobo has shown in his time at Fenerbahce his experience, professionalism, and an exemplary attitude. We wish him success with his new club for the rest of the season."