Pape Matar Sarr has 18 caps for Senegal
The Senegal international, 21, has played 18 times for Ange Postecoglou's side in the Premier League this season.
The new deal keeps him at the club until the summer of 2030.
Sarr has been named in Senegal's squad for this month's Africa Cup of Nations (Afcon), but his participation may be in doubt after he went off injured in Sunday's 3-1 win over Bournemouth.
After scoring the opening goal, Sarr left the field in the first half in tears, with Senegal's Afcon campaign in the Ivory Coast starting on 15 January against Gambia.
Sarr joined Tottenham from Metz in 2021 but spent the 2021-22 season back on loan with the French side.
Since making his Spurs debut in January 2023, Sarr has made 33 appearances in all competitions, scoring twice.
-- Courtesy of BBC Sport