The 26-year-old has made three England appearances and helped Leicester City win the FA Cup for the first time in club history in 2021.
After moving from Norwich to Leicester for around £20 million in 2018, he made 203 appearances.
Maddison scored 10 Premier League goals last season but couldn't keep the team from relegation.
Maddison, a Coventry native, led Leicester City with 55 goals and 41 assists last year. His flair will be a welcome addition to a Spurs team that has been without a top-tier playmaker since Christian Eriksen left in 2020.
Welcome, @Madders10! 🎯 pic.twitter.com/Jcm3Z1HEMU
— Tottenham Hotspur (@SpursOfficial) June 28, 2023
Newcastle previously sought to sign Madison but appears to have shifted their focus this summer to AC Milan's Sandro Tonali.
Tottenham signed Italian goalkeeper Guglielmo Vicario from Serie A club Empoli on Tuesday and has also extended Sweden midfielder Dejan Kulusevski's loan transfer from Juventus since the arrival of new manager Ange Postecoglou.
Spurs will want to keep England forward Harry Kane, who is expected to receive a higher offer from Bayern Munich.
According to insiders at Tottenham, Bayern Munich allegedly made a £70 million offer for England captain Wayne Rooney on Tuesday.
Harry Winks of Tottenham, a midfielder, is not expected to team up with Maddison. Winks is about to sign a £10 million transfer deal with Leicester.
With Youri Tielemans already committing to Aston Villa on a free transfer, Maddison joins the exodus from Leicester following the club's relegation to the Championship.
The Foxes second-tier season will begin against Coventry, a nearby rival.