It is understood Michael Carrick will look after affairs before the club appoint an external candidate in the next 24 to 48 hours to take charge on a caretaker basis for the rest of the season.
A statement from the club said: “Manchester United announces that manager Jose Mourinho has left the club with immediate effect. The club would like to thank Jose for his work during his time at Manchester United and to wish him success in the future.
“A new caretaker manager will be appointed until the end of the current season, while the club conducts a thorough recruitment process for a new, full-time manager.
Mourinho’s relationship with key members of his playing squad appeared to have disintegrated this season, with a public training-ground face-off with Paul Pogba and club captain Antonio Valencia being forced to apologise for ‘liking’ an Instagram post calling for Mourinho to be sacked.