Paltrow, who will be 40 in a couple of weeks, grabbed the top spot in the list by People magazine and her stylist said the actress owes it to her secret - less is more, Daily Mail reported.
The Duchess, 30, was just behind Paltrow on the list, and was hailed for her "flawlessly elegant attire".
Hollywood actresses Emma Stone, 23, Jessica Alba, 31, the Kardashian sisters and Australian supermodel Miranda Kerr, 29, were also included in the list.
Rihanna scooped the Best Risk-Taking Style Award and Kerr won the Best Street Style Award.
Among men, honours went to actors Andrew Garfield, Brad Pitt, Colin Firth, Robert Pattinson, Chris and Liam Hemsworth and singer Jay-Z.