Gavin Skelton has stood down as Queen of the South manager after only six months in charge.
The Scottish Championship club say the 35-year-old "left his position as manager for personal reasons".
Football development manager Jim Thomson has taken over as caretaker "until a replacement is appointed".
Queens, who only lost one of the first 12 games of the season, have dropped from top of the table to sixth amid a run of one win in their next eight.
Skelton's side suffered a 4-1 home defeat by second-top Dundee United on Saturday, but afterwards he told BBC Scotland he was looking forward to next week's Challenge Cup quarter-final at home to Alloa Athletic.
"It's a nice break from the league - the quarter-final of a cup - really looking forward to it," he said while admitting that the performance against United was poor.
Englishman Skelton, a midfielder with Carlisle United, Workington, Gretna, Kilmarnock, Hamilton Academical and Barrow, joined Queens in summer 2015 to become assistant to James Fowler.
Skelton had been manager at Northern Premier League outfit Workington.
He took over as caretaker in April after Fowler exited Queens, who had failed to reach the promotion play-offs, and was given the job permanently this summer.
Queens Mad are extremely sorry that things did not work out for Gavin and we wish him all the best in the future.