The Argentine has left his job at Southampton to take the position at White Hart Lane.
Pochettino said: "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."
Chairman Daniel Levy added: "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."
Jesús Pérez (assistant coach), Miguel D'Agostino (first team coach) and Toni Jiménez (goalkeeper coach) with whom Pochettino previously worked with at both Southampton and Espanyol, have joined him at White Hart Lane.
Pochettino guided Saints to an eighth-place finish in the Premier League this term and earned positive reviews for bringing an entertaining style to a young fresh team.
However, the team risks losing a number of their stars in the summer with Adam Lallana, Luke Shaw and Dejan Lovren all heavily linked with moves away from the club.
Tottenham are without a manager after sacking Tim Sherwood at the end of the season.
Southampton confirmed they had accepted Pochettino resignation after agreeing a compensation deal with Spurs.
Bookmakers have made Basel coach Murat Yakin as the early favourite to replace Pochettino.
Chairman Ralph Krueger commented: "The club has been on a constant path of growth since the arrival of Markus Liebherr in 2009. This growth took place before Mauricio came, it continued strongly under his leadership, and it will continue into the next season. The board’s job is to find opportunity in this challenge and to continue to move the club forward.
"We have begun the search for a new high-calibre manager. We will be looking for a manager that shares our values, our principles and our philosophy; a manager who can continue to grow the first team and build on our strong foundation – a foundation led by an ambitious vision and plan that continues to build on our world-class academy, our amazing 129-year heritage and our excellent staff, and rewards our loyal and passionate fan base.”
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