The Portuguese coach has left Spurs after just 17 months in charge and just a week before the club's League Cup final against Manchester City.
In a statement, Tottenham chairman Daniel Levy said: "Jose and his coaching staff have been with us through some of our most challenging times as a club.
"Jose is a true professional who showed enormous resilience during the pandemic. On a personal level I have enjoyed working with him and regret that things have not worked out as we both had envisaged. He will always be welcome here and we should like to thank him and his coaching staff for their contribution."
Mourinho took charge of Spurs in November 2019 and guided the club to Europa League qualification in his first season in charge.
They started this campaign in promising fashion but have lost form since Christmas and crashed out of Europe in the last 16 to Dinamo Zagreb while also sitting seventh in the Premier League.
The former Manchester United boss had criticised his players in recent weeks and accused his team of "hiding" in the loss to Arsenal last month.
Mourinho said: "No intensity, no pressing. In terms of creating attacking football, some important players were hiding. In the second half we only had to improve which we did."
He also seemed to suggest that the players were responsible for continuously letting leads slip after the recent draw with Newcastle.
Mourinho said after the game: "It was not a problem of fight, it was not a problem of attitude, the players wanted to win but I have to be honest and say I saw things on the pitch, not in terms of attitude but in terms of profile, vision, balance, which belongs to the top players, I didn't see in every position."