The 29-year-old, who has made two appearances for England, will be contracted to the club until 2018, with the option of a further year.
"Nick is a model of integration who perfectly fits our game and progresses it through his performance and involvement," said Clermont's sporting director Jean-Marc Lhermet.
Clermont head coach Franck Azema added: "We can only be satisfied and happy to extend Nick's contract for several seasons. Throughout last season he took the initiative and pushed the group forward."
Abendanon was voted European Player of the Year in 2014 following Clermont's campaign to the European Champions Cup final.