The 24-year-old Dutchman, who has scored five goals in 69 appearances for the Black Cats, will stay at the club until 2020.
Van Aanholt made an inconsistent start on Wearside after signing from Chelsea in 2014, but played a key role in his side's ride to Premier League safety last season.
Sunderland boss Sam Allardyce said: " Patrick was an outstanding performer last season, contributing not only solid defensive performances, but also assists and vital goals
"It is fantastic to be able to secure the long-term services of such a talented footballer and athlete, who will hopefully continue to improve here for many years to come."
Source : PA
Source: PA