The 34-year-old's appointment marks his return to the Barclays Premier League just four months after his departure from Chelsea, where he was sacked eight months into a three-year contract.
Villas-Boas will be hoping to rebuild his reputation at Spurs after succeeding Harry Redknapp, who left the post last month after four years at the helm.
The Portuguese has penned a three-year deal at White Hart Lane and brings with him two members of his coaching staff in the form of first-team fitness coach Jose Mario Rocha and Daniel Sousa, head of opposition scouting.
"Tottenham Hotspur is a great club with a strong tradition and fantastic support, both at home and throughout the world," Villas-Boas said.
"I feel privileged to be its coach. For me, this is one of the most exciting coaching positions in the Premier League.
"I have had several discussions with the chairman and the board and I share their vision for the club's future progress.
"This is a squad any coach would love to work with and together I believe we can bring success in the seasons ahead."
Chairman Daniel Levy said: "I'm delighted that Andre has agreed to become our head coach.
"He has an outstanding reputation for his technical knowledge of the game and for creating well-organised teams capable of playing football in an attractive and attacking style."