Pochettino becomes new Spurs boss
Pochettino has signed a five-year contract at White Hart Lane, bringing an end to his 16 months in charge at Southampton, with the South Coast club announcing his resignation on Tuesday.
The Argentine, who won 23 of his 60 games in charge of the Saints, told Tottenham's official website: "This is a club with tremendous history and prestige and I am honoured to have been given this opportunity to be its head coach.
"There is an abundance of top-class talent at the club and I am looking forward to starting work with the squad.
"Tottenham Hotspur has a huge following across the world and I have great admiration for the passion the fans show for this team. We are determined to give the supporters the kind of attacking football and success that we are all looking to achieve."
Former Espanyol coach Pochettino took over at Southampton in January 2013, replacing Nigel Adkins, and made a positive impression during the campaign, leading the club to 14th in the Premier League.
In his most recent season, the Saints received many plaudits for their style of football and the progress of his squad, including Adam Lallana and Luke Shaw, as they finished eighth.
Tottenham, meanwhile, have been seeking a new manager since the departure of Tim Sherwood, who failed to keep his job after succeeding Andre Villas-Boas in December and ending the season in sixth.
Spurs chairman Daniel Levy said: "In Mauricio I believe we have a head coach who, with his high energy, attacking football, will embrace the style of play we associate with our club.
"He has a proven ability to develop each player as an individual, whilst building great team spirit and a winning mentality. We have a talented squad that Mauricio is excited to be coaching next season."