Robertson enjoyed a glittering career on Merseyside after joining from Hull in 2017, registering 378 appearances and winning the Champions League, the FA Cup, two League Cups and two Premier League titles, including his second domestic crown in 2025.
Commenting on the transfer, Tottenham's sporting director Johan Lange said: "His quality, character and leadership have been evident throughout a career in which he has regularly competed for - and won - major honours. Andy's professionalism and commitment will also be invaluable to the development of our squad, and he shares our ambition and determination to bring success back to the club."