The Englishman's reign has lasted just six matches, with the capitulation against Melbourne Victory on Saturday the final straw
Ian Crook will stand down as Sydney FC coach after overseeing the Sky Blues' disastrous start to the 2012-13 A-League season.
The Englishman will officially announce his decision at a press conference to be held at Allianz Stadium at 2pm local time on Sunday.
His resignation comes less than 24 hours after Sydney squandered a 2-0 lead in going down 3-2 to Melbourne Victory.
The Sky Blues were coming off a 7-2 thrashing at the hands of Central Coast.
The A-League's glamour club has won just two from six under Crook and he felt he could not get the best out of the team.
Assistant Steve Corica is likely to step in as caretaker while the search for a new full-time coach begins.