Spurs had been trying to tie up a deal for Adebayor all summer, with the striker having enjoyed a successful loan spell at White Hart Lane last season.
It had been feared the move might break down over money but both clubs confirmed on Tuesday afternoon an agreement had been reached, while Adebayor himself tweeted: "I'm back!!!! Tottenham here I come!! I'm hungry for goals...Get ready."
Sources close to Tottenham have insisted the club have not broken their wage structure to sign the 28-year-old, who was reportedly on ?175,000 a week at City and reluctant to take a big pay cut.
It would seem the hold up was more the result of a dispute between the player and the Barclays Premier League champions over a loyalty bonus pay-off.
Adebayor spent three years at City but fell out of favour upon Robert Mancini's appointment as manager and spent the last year and a half on loan at Real Madrid and Spurs.
Despite having become a hate figure among Tottenham fans because of his days at Arsenal, Adebayor quickly won them over with a string of outstanding displays and finished last season as their top scorer with 18 goals in 37 appearances.
He told the club's official website: "I am pleased to be signing for Spurs on a permanent basis after finally agreeing my departure with Manchester City.
"It may have taken longer than expected but I am delighted to be back at Tottenham Hotspur.
"I really enjoyed my time here last season and I am hoping we can achieve great things together again."
Adebayor's arrival should end Spurs' search for a new centre-forward, with Jermain Defoe their only recognised out-and-out senior striker in Saturday's Premier League opening-day defeat at Newcastle.
But it is unlikely to herald the end of their summer transfer business, with QPR having made a bid for Michael Dawson on Tuesday afternoon, hot on the heels of fellow defender Sebastien Bassong's move to Norwich.
There are also reports Tom Huddlestone, Jermaine Jenas, David Bentley and Giovani dos Santos could find themselves surplus to requirements under new manager Andre Villas-Boas.