The 33-year-old was tasked with getting Southampton back to the Premier League at the first time of asking following their relegation from the English top flight at season.
With just four wins from his 16 games in charge, Still has been dismissed with Southampton down in 21st, three points off the relegation zone.
Ruben Martinez, Clément Lemaitre, and Carl Martin have stepped down from their roles on the club’s coaching staff, leaving men’s Under-21s head coach Tonda Eckert to oversee the team on an interim basis.
According to The Athletic’s David Ornstein, Eckert is highly regarded at the club and is under consideration to replace Still on a permanent basis.
“Will is a great person who gave everything to try and improve performances and results,” group technical director Johannes Spors said in a statement.
“Ultimately that process has taken longer than any of us would have liked. By making a change now we believe it gives us the best chance of turning things around this season and climbing back up the league table.
“I would like to thank Will, Rubén, Clément and Carl for their efforts and wish them well for the future.”