The silence will be observed before all Premiership and Football League games this weekend.
Sir Bobby Charlton, a director at Old Trafford and a team-mate of Best's during his time at the club, said: "Manchester United's glorious history has been created by people like George Best.
"Anyone that witnessed what George could do on the pitch wished they could do the same. He made an immense contribution to the game, and enriched the lives of everyone that saw him play.
"Football has lost one of its greats, and I have lost a dear friend. He was a marvellous person and my thoughts are now with his family."