The United boss is celebrating 25 years in charge at Old Trafford and United chief executive David Gill made the announcement before the match with Sunderland on Saturday.
Gill also revealed that a statue of Sir Alex will be placed outside the Sir Alex Ferguson stand.
Gill said: “To be at a club of our standing for so long is truly remarkable.
“In that time Alex has established himself as the most successful manager in British football history, winning countless trophies and creating numerous sides admired around the world for their flair and ability.
“Alex’s contribution to United has been immense and the magnificent stadium we have here at Old Trafford is a testament to his ability and success.
“The board felt it right to take this unique step, as well as to commission Philip Jackson to create a statue to go alongside his other great pieces here of Sir Matt and the United Trinity.
“These tributes are made with the grateful thanks of the owners, board, staff, players and fans of Manchester United, for the great pleasure Alex has brought us all over a quarter of a century.”
