The Spanish manager has spent three seasons at the club
Everton have confirmed the sacking of manager Roberto Martinez with immediate effect.
Martinez replaced David Moyes as Everton manager in 2013 on a four-year deal before signing a new five-year contract last summer. The former Wigan manager was fresh off winning the FA Cup - and relegation - with the team before moving to Liverpool.
The 42-year-old was only the 14th ever permanent manager of the club, and the first from outside Britain and Ireland.
In a short statement on the club's website, Everton said: "Everton Football Club regrets to announce that Roberto Martinez has left his position as First Team Manager with immediate effect.
"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. 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 semi-finals. 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."
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 Spaniard's first season at Goodison Park was his most successful as he led the team to a fifth-placed finish in the league. The following year, Everton reached the last-16 of the Europa League, but their league form dipped as the team finished in 11th.
This season has been Martinez's most disappointing domestically. Despite reaching the FA Cup semi-final, the team have struggled badly in the league and currently lie in 12th place ahead of their last league game of the season.
The last two games has seen the side lose 3-0 away to both champions Leicester City and Sunderland. Everton's final game of the season is at home to Norwich.