The Argentinian has been relieved of his duties after five-and-a-half years in charge.
Spurs, who were in the Champions League final only six months ago, have endured a tough start to the season and are currently 14th in the Premier League table.
Chairman Daniel Levy, who appointed Pochettino in June 2014, said: “We were extremely reluctant to make this change and it is not a decision the board have taken lightly, nor in haste.
“Regrettably domestic results at the end of last season and the beginning of this season have been extremely disappointing.
“It falls on the board to make the difficult decisions – this one made more so given the many memorable moments we have had with Mauricio and his coaching staff – but we do so in the club’s best interests.”