She is to have announced her decision during a staff meeting.
The now 75-year-old Wintour started at Vogue as early as 1988 and has since achieved legendary status within the fashion industry. She has during her long career, among other things, been behind the then groundbreaking development of having celebrities on the magazine cover.
Even though she is now leaving as editor-in-chief, she will remain at the magazine as global editorial director. In addition, she retains the role of global content director at Vogue's publisher Condé Nast as well as the responsibility for the star-studded fashion event Met Gala.
A source with insight states to the news agency AP that Vogue will not appoint a new editor-in-chief, but rather is looking for someone who can lead the daily work, subordinate to Wintour. This is to give Wintour more time to devote to her other commitments.