Tanguy Ndombele and Davinson Sanchez were both club-record signings for Tottenham
France midfielder Ndombele, 26, joins the Turkish champions on a season-long loan with an option to buy for £12.8m.
Colombia defender Sanchez, 27, has signed a four-year deal with the option of a further season after Galatasaray agreed an £8.1m fee for the player.
Sanchez arrived at Spurs in 2017 for a reported £42m, while Ndombele was a £55m acquisition in 2019.
Both were club-record signings for Tottenham but neither have started a Premier League fixture this term under new boss Ange Postecoglou.
This is Ndombele's third loan spell away from Tottenham, having previously had stints with former club Lyon and Serie A winners Napoli.
Sanchez leaves Tottenham after six years at the club following his move from Ajax in 2017. He made 207 appearances in all competitions, scoring five goals.
-- Courtesy of BBC Sport