Willian has signed a one-year contract with Fulham after rejecting an offer from Nottingham Forest.
The former Chelsea winger joined the Whites last summer on a free transfer after returning to London after a difficult spell with hometown club Corinthians in Brazil.
He enjoyed a superb Premier League campaign, with five goals in 27 appearances.
Manager Marco Silva said at the end of last season that keeping the 34-year-old at Craven Cottage was a priority.
“I’m completely happy. Happy to continue the work I did last season with all my team-mates and the whole club,” Willian said.
“I think it’s a club that can do even better this season, so I’m happy to continue this amazing adventure.”