The 20-year-old England youth international’s impressive performances this season were beginning to attract interest from some of Europe’s biggest clubs including Bayern Munich and Arsenal.
Lamptey joined Brighton from Chelsea in January last year and has been a revelation for Graham Potter’s men, although he has missed Brighton’s last seven games through injury.
Lamptey has made 11 appearances this season and 19 in total since moving to the Amex stadium.
"We are delighted to see Tariq commit his long-term future here," Brighton boss Potter said via the club's website.
"We knew his potential when we signed him a year ago, and hoped he would have a really positive impact on the club, and that has proved to be the case with his performances since June.
"He has been the model professional, he works exceptionally hard, is a humble lad and is a team player. He fits in with everything we would want from a player, now it's about helping him reach his potential."
Brighton’s technical director Dan Ashworth added: 'He fully deserves the new contract and has earned it with his hard work and performances.'
'It now gives him and the club the opportunity to continue on the path he has started on since he joined last January.'
