The 36-year-old, who has turned down options to remain in F1, will join Porsche's new sports car programme, as rumours emerge claiming that Lotus's Kimi Raikkonen will replace the Australian at Red Bull.
"Porsche has written racing history as a manufacturer and stands for outstanding performance and technology at the highest level," said Webber.
"I'm very much looking forward to this new challenge after my time in Formula 1. I can hardly wait to pilot one of the fastest sports cars in the world."
Webber, who has finished third twice in the World Championship, has won nine grands prix and reached 36 podium finishes in 12 years in the sport.