Huddersfield have appointed first-team coach Mark Hudson as caretaker manager after the departure of Jan Siewert.
Siewert was sacked soon after Friday night's home defeat to Fulham, which extended the Terriers winless start to four matches this season.
The 36-year-old German won only one of his 19 games in charge after replacing David Wagner in January.
"First-team coach Mark Hudson will take temporary charge of the team, beginning with the Sky Bet Championship game at Cardiff City on Wednesday evening," Huddersfield said in a statement.
Club chairman Phil Hodgkinson said Siewert had had little impact on the team's performances during his seven months in charge.
The Terriers had defied the odds to survive their first season in the Premier League under Wagner.
But they were eight points from safety after 22 games when Siewert took over at the turn of the year and after winning only one of their remaining 15 games, relegation was confirmed in March.
"Last night's decision was not one that I, nor the board, took lightly, but I believe it is one that had to be made," Hodgkinson said in a statement.
"Jan walked into a very difficult situation in January; something that we were all aware, and mindful, of.
"However, I have seen no evidence of the impact on our performances that I was expecting following a full pre-season.
"Jan is a fantastic man and he's worked tirelessly for this club during his time here, but unfortunately it has not worked.
"I believe he is a good coach and I sincerely hope he will be successful in the future.
"I believe our players are better than we have seen so far this season. We will work to appoint a new head coach who can get the best from them and bring an identity back to our performances."