Earlier on Friday, Mauricio Pochettino revealed that he wanted to sign four new players, and the first one of those is highly-rated Sanchez, who will pen a six-year contract in North London.
The completion of the transfer is subject to a medical being passed and a work permit being granted, but Sanchez has already spoken of his delight having agreed terms with the Premier League side.
The 21-year-old told the club’s official website: “I would like to thank the coach, management, players and fans of Ajax. It is a great move for me to come here to develop my career.
“I am very excited to be signing for such a famous club as Tottenham Hotspur. I am looking forward to working with Mauricio Pochettino and the players and meeting everyone there.”
The Colombian international – who had previously been linked with the likes of Manchester United, Chelsea and Barcelona – leaves Ajax having netted six times in 44 appearances in all competition, as well as playing a key role in their run to last season’s Europa League final.