Pitkethly, who has been with the maker of Dove soap since 2002, succeeded Jean-Marc Huët as finance chief in 2015.
The 56-year-old previously served as executive vice president of Unilever's UK and Ireland business, including head of M&A and head of treasury.
Commenting on the news, Unilever chief executive Alan Jope said, “I would like to thank Graeme for his tremendous contribution to Unilever over the last 21 years. As CFO, he has brought great leadership to our company and been instrumental in sharpening our strategy and driving a step-up in our operational performance.”
Unilever said it would proceed with a formal internal and external search for Pitkethly's successor.
Elsewhere, Conny Braams, who currently serves as the chief digital and commercial officer, and is a member of the Unilever Leadership Executive (ULE), has announced plans to depart from Unilever in August 2023.
Conny joined the ULE in January 2020 and has held various distinguished positions within the company, such as Executive Vice President (EVP) for Middle Europe, as well as EVP Foodsolutions Asia, Africa, and Middle East.
Earlier this year, Unilever appointed the former chief of Dutch dairy business FrieslandCampina, Hein Schumacher, to replace Alan Jope as chief executive from July.
One of the biggest consumer companies in the world with more than 400 brands ranging from detergent to ice cream, Unilever said last year that Jope planned to retire at the end of 2023.