
Poyet left his job as assistant coach at Leeds United and will work as one of two first-team coaches alongside Marcos Alvarez, underneath head coach Juande Ramos.
Ramos replaced Martin Jol as manager on Saturday after the Dutchman was sacked last week.
"We are delighted to announce the appointment of Gus Poyet to our coaching staff," Tottenham said in a statement.
Poyet played at White Hart Lane for three seasons between 2001 and 2004.
Tottenham are currently stuck in the relegation zone in the English Premier League after just one win from their first 11 matches.
DPA