He will be replaced by Marc Pritchard, the company's president of strategy, who was responsible for P&G's recent global restructure.
Stengel, 53, now plans to write a book and will work on a number of projects.
Pritchard takes over on 1 August when Stengel moves on to special projects. Stengel will leave the company for good on 31 October.
Stengel, who took over as the global marketing officer in 2001, has since become an advocate of creativity. He and the company's chairman and chief executive, AG Lafley, collected the Advertiser of the Year award at Cannes last month.
The company won 13 Lions at this year's ceremony, including a gold in the Film category for Saatchi & Saatchi New York's Crest work. Since 2003, it has picked up 53 Lions in total. Stengel joined P&G in 1983 as a brand assistant.