The Senegal international joined the Potters on January 31 for a fee of £14 million from the Yellow-Reds and featured in 14 league games, scoring twice.
However, he could not help the Bet365 Stadium outfit from dropping to the Championship after finishing in the 19th spot with only 33 points from 38 games last season.
On Tuesday, the Potters announced that the midfielder has completed a temporary move to his former club.
“Badou Ndiaye has today re-joined Galatasaray on loan from Stoke City for the remainder of the 2018/19 season,” read a statement from the club website.
“The 27-year-old Senegal international joined the Potters from the Turkish side in January and has made 14 league appearances for the Club.”
The midfielder could make his first appearance in the 2018-19 season for the side when they clash with Trabzonspor on Saturday.