The South Korea global, who joined from Bayer Leverkusen in 2015, has pledged his future to the London club until the end of the 2022-23 season.
Son took his fine goalscoring touch to the World Cup in Russian Federation where he scored twice for South Korea, including the second in a memorable 2-0 group stage win over 2014 winners Germany.
The 26-year-old has scored 47 goals in 140 appearances for Tottenham since signing from Bayer Leverkusen in 2015, making him the top Asian scorer in Premier League history.
"I've learned so many things in the last three years and we're all looking forward", he said on the club's official website.
He returned from injury last November as a substitute against Leicester City, but started just 12 times in his 33 appearances during 2017-18. It's time to do it and to believe in ourselves.
"I'm always positive with the lads and looking forward to playing again in the Premier League and the Champions League".
He began his pre-season with a first-half hat-trick in Tottenham's friendly against Southend and will be part of the club's pre-season tour of the United States.
Pochettino's squad will compete in the International Champions Cup, with matches against AS Roma (San Diego), Barcelona (Los Angeles) and AC Milan (Minneapolis).