The Portuguese coach was given his marching orders after a series of poor results saw the club throw away a title challenge, crash out of the Europa League and drop out of the top four, amid reports of dressing room unrest following the outspoken manager's repeated public criticism of the team.
Here's everything you need to know about the man stepping into Mourinho's shoes:
Who is Ryan Mason?
The 29-year-old is a former football, who came up through the Spurs youth academy and ended up making over fifty appearances for the club.
He spent time on loan with the likes of Millwall, Doncaster Rovers and French side Lorient, before breaking into the Spurs side in 2014 and earning an England senior cap the following year.
When did he retire from playing, and why?
After falling out of favour at Spurs, Mason secured a £13m move to Hull City in 2016.
His career came to an end in his first season with the Tigers, after a clash of heads with Chelsea's Gary Cahill saw him suffer a fractured skull.
After struggling with recovery despite relentless efforts to return to the game, Mason announced in 2018 that he would be retiring after a number of medical professionals advised that continuing to play could pose a severe risk to his health.
What coaching experience does he have?
Soon after announcing his retirement, the ex-England international took an academy role at Spurs, where he worked to earn his coaching badges.
He's since become the club's head of player development.
What are his odds of getting the job on a permanent basis?
He's currently a fairly distant 12/1 to become Spurs' next permanent manager.
RB Leipzig boss Julian Nagelsmann is the early favourite (5/2) for the job, ahead of Brendan Rodgers (4/1) and Eddie Howe (6/1)