The new deal will keep the Tunisia international at the club until the summer of 2016.
The 22-year-old has recently been linked with the likes of Arsenal and Stoke.
“His adaptation to Ligue 1 has been a real success and he’s a player who has a great future ahead of him,” said Toulouse coach Alain Casanova.
Abdennour joined Toulouse from Tunisian side Etoile du Sahel in 2011.
