Thomas Frank has been sacked by Tottenham after just under eight months in charge following their dismal 2-1 defeat at home against Newcastle on Tuesday.
Spurs are 16th in the Premier League and just five points above the relegation zone following a dreadful run of form.
The north London side are winless in their past eight Premier League games - their longest run without a victory since October 2008.
They have won just two of their past 17 league matches and picked up only 12 points in that time.
Tottenham said they had been "determined to give Frank the time and support needed to build for the future together", but recent results meant "a change at this point is necessary".
Frank took over as head coach in June after Ange Postecoglou was sacked and signed a deal until 2028, but proved unable to notably improve the club's league form despite strong results in European competition.
Against a mixed Premier League record of seven wins, eight draws and 11 defeats this season, the Dane led Spurs to automatic qualification for the last 16 of the Champions League by finishing fourth in the group stage.
However, they are out of both domestic cup competitions, having been beaten by Newcastle in the fourth round of the Carabao Cup in October and Aston Villa in the FA Cup third round last month.
"Throughout his time at the club, Thomas has conducted himself with unwavering commitment, giving everything in his efforts to move the club forward," Tottenham said.
"We would like to thank him for his contribution and wish him every success in the future."
Despite the loss to Newcastle, Frank still expected to be in charge for the north London derby against Arsenal on 22 February.
Asked by TNT Sports on Tuesday night if his job was under threat, Frank said: "I spoke to them [the owners] yesterday, so no.
"I understand the frustration and the easiest thing is to point at me. That's part of the job unfortunately.
"I will work day and night to turn this around but it is not just one person. There is no doubt we need to improve and I need to be part of that."
Spurs were loudly booed after the defeats at home by Newcastle and fellow strugglers West Ham in the past few weeks.
Frank was also taunted by his own fans with chants of "you're getting sacked in the morning" during the loss to West Ham and the 2-2 draw at Burnley that followed.
After being booed off at half-time while 2-0 down to Manchester City, Frank's side responded to draw 2-2 at Tottenham Hotspur Stadium.
Captain Cristian Romero was critical of Tottenham's board after that result, calling it "disgraceful" that the club only had 11 fit senior players available against City.
The Argentine then received a straight red card - his second of the season - against Manchester United on 7 February, who went on to win 2-0.