The 27-year-old has helped the Bluebirds to two wins and two draws in his five games with the club, the only blip coming in a 2-1 defeat at struggling Peterborough.
Boss Malky Mackay told the club's official website: "Thanks to the support of Chris Hughton and Norwich City, Leon Barnett will be staying with us until the end of the season.
"We are very grateful to Norwich for their help and look forward to Leon continuing his impressive form in a Cardiff City shirt for our remaining games."
The loan will run until May 31, enabling Barnett to participate in the play-offs should Cardiff drop out of automatic promotion contention.
- Sports & Recreation
- Leon Barnett
- Chris Hughton