Paul Heckingbottom has been sacked as Hibernian head coach with the Leith club languishing 10th in the Scottish Premiership.
His exit, along with assistant Robbie Stockdale, comes after Hibs shipped five goals to Celtic in Saturday's League Cup semi-final defeat.
The Englishman had been in charge for almost nine months.
Head of player development Eddie May will take temporary charge supported by Grant Murray and Steven Whittaker.
A club statement said further comment can be expected "in the coming days".
Although unbeaten in his first 10 league games as boss, guiding Hibs from eighth to fifth, his team took nine points from a possible 33 this term.
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The 42-year-old has overseen 32 games as Hibs head coach, winning 12, drawing 11 and losing nine.
After succeeding Neil Lennon in February, Heckingbottom successfully led Hibs to a fifth-placed finish, but their form declined at the end of the campaign, and they failed to win any of their five post-split matches.
The former Barnsley and Leeds United boss came under pressure early in the current season as his nine summer signings failed to make a telling impact.
His reluctance to recruit a like-for-like replacement for powerful defensive midfielders Marvin Bartley and Mark Milligan, both of whom left at the end of last term, left Hibs vulnerable at the back, with their goal difference dropping to -10.
Hibs have not won a league game since a last-gasp victory over St Mirren on the opening day of the campaign. They shipped six goals in a heavy loss to Rangers at Ibrox, were held at home by St Johnstone, Ross County and Livingston and were easily swept aside at Motherwell and Kilmarnock.
In September they surrendered a 1-0 lead at home to struggling rivals Hearts, who were winless in 12 top-flight matches, allowed the Tynecastle side to leapfrog Hibs.
Heckingbottom's departure means both of Edinburgh's Premiership clubs are looking for a new manager after Craig Levein left Hearts last week.
'Heckingbottom pays price for recruitment' - analysis
Former Hibernian midfielder Michael Stewart on Sportsound
The Hibs supporters have not been happy for a long time. I think Paul Heckingbottom's problem has been his recruitment in the summer, it just has not worked.
He let go of some players that I think would be doing a lot better than the guys that he's brought in and he's ultimately paid the price because of that recruitment in the summer that has left a gaping hole through the spine of their team.