The 51-year-old Danish coach joined Spurs from Brentford in June, replacing Ange Postecoglou who, despite winning the Europa League and ending a 17-year trophy drought, was sacked after guiding the club to a 17th-place finish in the Premier League.
The loss to the Magpies followed a prolonged slide in results and growing dissatisfaction among supporters and the board, and was widely viewed internally as the final straw.
The club announced the sacking on X by saying: "The Club has taken the decision to make a change in the Men’s Head Coach position and Thomas Frank will leave today.
"Thomas was appointed in June 2025, and we have been determined to give him the time and support needed to build for the future together.
"However, results and performances have led the Board to conclude that a change at this point in the season is necessary.
"Throughout his time at the Club, Thomas has conducted himself with unwavering commitment, giving everything in his efforts to move the Club forward. We would like to thank him for his contribution and wish him every success in the future."
His official sacking means Tottenham are now searching for their fifth permanent manager since the 2019 departure of Mauricio Pochettino, who is now one of the leading candidates for the role.
Frank arrived from Brentford with a reputation as one of English football's shrewder operators, a coach who had navigated the Bees from Championship contenders to established Premier League competitors.
His Spurs contract ran until 2028, but the promise of long-term stability was undermined by uneven results and a style that never fully convinced.
Alarming results
Despite a solid start, he was unable to steady the ship left by his predecessor and leaves the post having won just seven of their 26 Premier League games, drawing eight and losing 11.
Home form was particularly alarming, with only two league wins in 13 matches, and a recurring inability to control games against perceived inferior opposition.
From 26 league matches, Frank has a win rate of just 26.9%.
Under Pochettino, Spurs won roughly 54 per cent of Premier League matches across nearly five seasons, with that figure rising above 60 per cent in his peak years. Jose Mourinho posted a league win percentage just above 51 per cent, despite a deteriorating squad and evident stylistic friction.
Antonio Conte, for all the volatility of his reign, still delivered a Premier League win rate of around 53 per cent, driven by a strong first full season.
Even under Postecoglou, whose final months were marked by defensive fragility and supporter unrest, delivered a league win rate hovering in the high 40s, comfortably ahead of Frank's output.
Damning losses to rivals - including a heavy 4-1 defeat away to Arsenal - did little to curry favour with fans, who also criticised the lack of attacking flair throughout his tenure.
The North London side also exited both domestic cups early, and while they have made the playoff stages of the Champions League, there is little expectation of a deep run in Europe's elite competition, while qualification for next year looks highly unlikely.
Pochettino, Oliver Glasner, Xabi Alonso and Marco Silva are among the front-runners to become the next permanent Spurs boss.