Having made his way through the prestigious youth system at the Eredvisie champions Van Rhijn was handed his first-team debut in September 2011.
The full-back has gone to cement a starting place with Frank de Boer's side and has made 107 appearances in all competitions.
With just a year left on his previous deal, Newcastle United had been credited with an interest in the 23-year-old, but he is now toed to the Amsterdam Arena until 2018.
Van Rhijn told the club's official website: "For a while it hung in the air, but it was clear that we wanted to extend.
"It's fine because now it is officially confirmed. This contract extension is a sign of quite a lot of confidence in me."
Van Rhijn has played a big role in the last three of Ajax's four consecutive Eredivisie title-winning campaigns.
His club form has earned him seven international caps with Netherlands, with his debut coming against neighbours Belgium in 2012.
