TheFork users who ate in Guyancourt have said really good things about Le Villaroy, CAJÙ Grill Restaurant and La Flambée - Montigny Btx. Maybe you should give them a try!
Some of the more popular Vegan dishes restaurants that offer vegan options on their menu in Guyancourt according to TheFork users include:
Le Villaroy, with a 9.4 rating
CAJÙ Grill Restaurant, with a 7.9 rating
La Flambée - Montigny Btx, with a 8.8 rating