The Olympic road race champion beat Ellen Van Dijk, Emma Johansson and Elisa Longo Borghini at the end of the 127.4km event.
Annemiek van Vleuten led the peloton over the line in fifth.
The 10th edition of the race saw the riders tackle 10 hills and the cobblestone sections of the Paddestraat and Haaghoek and Dutch star Vos claimed her first Flanders success, one of the few races missing from her illustrious palmares.
She also triumphed in the opening World Cup race of the season, the Tour of Drenthe.
- Sports & Recreation