Giovanni van Bronckhorst sacked by Rangers after one year in charge at Ibrox.
Rangers are currently nine points behind leaders Celtic in the Scottish Premiership.
Rangers also endured a sobering Champions League campaign which saw the club lose all six group stage matches, a run that included a 7-1 hammering by Liverpool at home.
Van Bronckhorst - who signed a three-and-a-half year deal to replace Steven Gerrard last November - becomes one of the shortest-serving permanent managers in the club's history, with only Pedro Caixinha and Paul Le Guen departing sooner.
The Scottish Premiership is now on hold for the World Cup, with Rangers' next game against Hibernian at Ibrox on December 15, live on Sky Sports.
Results and performances haven't met expectations
A Rangers statement said: "Rangers Football Club confirms today it has parted company with manager Giovanni van Bronckhorst. The board would like to put on record sincere thanks to Gio for all his efforts since his appointment as manager.
"Arriving at the club just over a year ago, Gio led the club to a fifth European final and won the Scottish Cup last May. He also led the team to the club's first Champions League qualification in 12 years.
"Unfortunately, results and performances over recent months haven't met expectations and the decision was made today by the board to terminate the contract of the manager.
"The search for the new manager is now underway."
Chairman, Douglas Park, commented: "I want to thank Gio for the hard work he has put in over the last 12 months and, especially, the achievements of taking the club to the Europa League final and winning the Scottish Cup last season.
"Unfortunately, recent results have not met neither our nor Gio's expectations, and we have taken this difficult decision today. Everyone at Rangers wishes Gio every success in the future."
Rangers' next five fixtures
December 15: Hibernian (h), Scottish Premiership, kick off 8pm, live on Sky Sports
December 20: Aberdeen (a), Scottish Premiership, kick off 8pm, live on Sky Sports
December 23: Ross County (a), Scottish Premiership, kick off 7.30pm, live on Sky Sports
December 28: Motherwell (h), Scottish Premiership, kick off 7.45pm
January 2: Celtic (h), Scottish Premiership, kick off 12.30pm, live on Sky Sports
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