Everton fired Ronald Koeman after 5-2 loss to Arsenal at Goodison Park in the Premier League encounter on Sunday, which left them in the relegation zone.
Everton have won just two league games and lost five after spending almost £140m in the summer.
A statement from the club said: “ Ronald Koeman is fired. Read Below.
“Chairman Bill Kenwright, the board of directors and major shareholder Farhad Moshiri would all like to express their gratitude to Ronald for the service he has given to the club over the past 16 months and for guiding the Club to seventh place in last season’s Premier League campaign.”
The 54-year-old Koeman became the third Premier League managerial casualty of the season after Frank de Boer left Crystal Palace and Craig Shakespeare was sacked by Leicester.
Everton part ways with former Southampton and Valencia manager after 16 months in charge having guided Toffees to seventh place last season
Everton will play Chelsea on Wednesday in the fourth round of Carabao Cup at the Stamford Bridge.