Everton confirmed the departure of manager Roberto Martinez with immediate effect on Thursday.
Martinez, who took charge in 2013 following David Moyes' exit, has been under heavy pressure for several weeks after a disappointing run of form and leaves the club 12th in the Premier League.
Everton have won just one of their last 10 matches in all competitions, and Wednesday's 3-0 defeat to Sunderland was their third straight away from home. They conceded 10 goals in those three games.
Everton Football Club regrets to announce that Roberto Martinez has left his position as First Team Manager with immediate effect.
- Everton (@Everton) May 12, 2016
"The Chairman and the Board of Directors would like to place on record their thanks for the dedication and commitment Roberto has shown during his three seasons with the Club. Roberto has been a great ambassador for the Club, conducting himself, at all times, with the utmost integrity and dignity," a statement read.
"He secured the Club its highest-ever Premier League points total, a place in the last 16 of the Europa League and appearances in both domestic cup semifinals.
"He has also played a key role in the development of several young players, managing their progression to the Everton First Team and International honours."
The Toffees have reached the semifinals of both the Capital One Cup and FA Cup this season, but were beaten in those competitions by Manchester City and Manchester United, respectively.
Fans have staged protests calling for the former Swansea City and Wigan Athletic boss to be sacked, and the club announced on Thursday that he had been relieved of his duties prior to the final game of the season against Norwich City on Sunday.
The club announced David Unsworth and Joe Royle will be in charge for Sunday's final game of the season against the Canaries.
Frank de Boer, who left Ajax on Thursday by mutual consent, has been linked with the vacancy after his agent recently told NOS that the former Netherlands international "would love to join a club like Everton or Valencia."
Speaking prior to the confirmation of Martinez's exit on Thursday, De Boer had told reporters that he is waiting for a suitable offer.
Asked specifically about Everton, he said: "I don't want to put Roberto Martinez under pressure, so let's wait and see."
De Boer's brother Ronald told Sky Sports on Thursday: "In my eyes he's the right man for the job but it's up to Everton to make their move."
Outgoing Manchester City boss Manuel Pellegrini and former boss Moyes are also seen to be among the contenders.
Everton also rescheduled their annual awards event that had been set for for Thursday evening, where fans had been expected to gather to protest Martinez.
"Roberto has shown great commitment and dignity throughout his time at Everton and the Club feels it should reciprocate by rescheduling the event," Everton said. "The Club hopes that those due to attend would agree that the planned celebration would be inappropriate in the circumstances."