Net-a-Porter chief executive Mark Sebba is to step down after 11 years in the role.
Sebba will continue to sit on the board as a non-executive director and headhunters have been hired to find a replacement, the luxury etailer said.
Net-a-Porter, which started in June 2000, has over 2.5 million visitors each month. It is majority owned by Swiss designer goods company Richemont, who took the stake for an estimated £50m in 2010, although chairwoman and founder Natalie Massenet continues to hold a stake in the company. The business was valued at the time at £350m.
Brand extensions The Outnet, a discount site, menswear etailer Mr Porter and magazine Porter are also run by the company.
Sebba has also this month been appointed as a trustee of the Victoria and Albert Museum.