US vice president Kamala Harris came in at number 2, following author and philanthropist Mackenzie Scott - who also happens to be the ex-wife of Amazon's Jeff Bezos.
In May this year, Ardern came in at the top of the Fortune World's Greatest Leaders list in recognition of her work to eliminate Covid-19 in New Zealand in 2020.
While the list includes 40 female CEOs this year, there are two fewer heads of state than there were on last year's list.
And BioNTech cofounder and immunologist Özlem Türeci has made her debut on the list at number 48 for her role in leading the company's development of the mRNA Covid vaccine in partnership with Pfizer.
You can read the full list of recipients here.