Loeb, who has taken the majority of his wins across a range of different racing disciplines behind the wheel of a Citroën, will move to sister Groupe PSA team Peugeot Sport for an assault on the Dakar Rally in 2016.
Speaking about his time with Citroën, Loeb said "Apart from the figures and the records, we have shared some magnificent experiences together."
"It's hard to believe that most of the members of this amazing team were already here fifteen years ago." added the 78 time World Rally and six time WTCC race winner. "I'll miss their hunger for success and limitless motivation, but I won't be far away - I'm staying within the PSA Peugeot Citroen group to take on a new challenge."
Speaking on Facebook, Loeb appeared to hint that his departure from Citroën was not his decision.
"I was surprised when I learned that I won't move forward to defend the colours of Citroën Racing in 2016," Loeb posted on his Facebook page."We built this challenge in WTCC together, with for personal goal to get the title drivers under three years."
Citroën CEO Linda Jackson was full of praise for Loeb following the announcement of his departure
"In the last fifteen years, Sebastien Loeb and Citroën have made history together," she said. "It has been an absolutely incredible period that will leaving a lasting mark in the world of motorsport.
"We would like to thank him for all these wins, titles and records, which have helped to renew the brand and boost its international reputation.
Following the conclusion of the WTCC season at the end of November Loeb's attention will turn to yet another new motorsport discipline when he becomes a full time member of Peugeot's Rally World Cup effort.
Loeb has already tested the diesel-powered 2008 DKR that he will drive on the Dakar Rally. He has also competed in the car during last month's Rallye du Maroc.
Loeb's début on the Dakar rally next year will not be the first time that Loeb has competed in a major event for Peugeot Sport. The Frenchman smashed the Pikes Peak hillclimb record by a minute and a half in 2013 behind the wheel of the Peugeot 208 T16.
Images: Flavien Duhamel, @World, @tWorld, Kin Marcin, Garth Milan/Red Bull Content Pool