Several European sides having been chasing the 27-year-old who has decided to turn down the improved terms on the table in favor of a fresh challenge elsewhere.
Munster chief executive Garrett Fitzgerald says everything was done to keep a player who has always wanted to play abroad and has made the decision in the best interests of his family.
"Working closely with the IRFU we put ourselves in the best position possible with an excellent offer, and while we are largely successful in retaining our best players within the Irish system we know it is out of our hands on this occasion," Fitzgerald said.
"We are hugely disappointed to see Simon leave but we wish to thank him for his immense contribution to the province and wish him and his family all the best for the future."
Which club Zebo will be joining has yet to be revealed but France is the likely destination, with Racing 92 favorites to do a deal.