The Belgium international finalises his move to north London after agreeing personal terms and passing a medical to become the second summer signing at White Hart Lane
The north London club agreed a fee with FC Twente on Sunday and the deal for the versatile Belgium international is now complete.
Chadli, who has 14 international caps to his name, scored 12 goals in the Eredivisie last season and will provide much-needed cover for Spurs in the final third.
A statement on Tottenham's official website read: "The Belgium international is expected to be available for the first time when we travel to Monaco for our pre-season fixture on Saturday, August 3."
Chadli is the second new arrival at Tottenham this summer after Brazil midfielder Paulinho joined for £17 million.