Dupont has starred for Les Bleus in an impressive 2021, culminating in a famous 40-25 victory against New Zealand in Paris last month in the final test of the Autumn Nations Series, their first win against the All Blacks since 2009.
The 25-year-old also impressed in the Six Nations, assisting five try – two more than anyone else in the competition – while adding three tries of his own and making the third most passes (261).
Dupont, who also helped Toulouse to a Heineken Champions Cup and French Top 14 double, was presented the award by France team-mate and long-term friend Anthony Jelonch.
On receiving the award, Dupont said: "It's hard to believe. Of course I have a lot of joy and pride. A lot of feelings and emotions that blend together.
"To be named alongside two French players, [former winners] Fabien Galthie and Thierry Dusautoir, you have players like [Richie] McCaw and [Dan] Carter, who have won three each I believe, they are legends of our sport so it's weird to see myself named in this list.
"You almost have the feeling of not deserving it. You have to do everything to be able to repeat it, and always keep performing, keep going and give more.
"I am very happy and proud to have been named 2021 Player of the Year. I can't wait to tell my loved ones and share it with them too."
England's Zoe Aldcroft was named the World Rugby Women's 15s Player of the Year, meanwhile, having started all eight of her nation's matches in 2021 as it extended its unbeaten run to 18 Tests.