The commercial appeal of the Premier League giants means they can do separate sponsorship deals for their training kit and the famous red shirts they play in.
It is the first time United have sold naming rights to their training ground in Carrington on the outskirts of Manchester in northern England.
"I am delighted this cements our relationship with Aon for a further eight years," said United commercial director Richard Arnold in a statement.
Financial terms of the new agreement with Aon, the world's largest insurance broker, were not disclosed.
United, owned by the American Glazer family, look set to win the top-flight title for a record 20th time this season. They have a virtually unassailable 15-point lead over second-placed Manchester City ahead of Monday's derby between the two teams.
Keen to reassure fans worried about the extent of the club's commercial ambitions, United said there were no plans to seek a sponsor for their stadium.
"Old Trafford will not be sold," executive vice-chairman Ed Woodward said, referring to naming rights for the club's home.
However, United's renewed success on the field this season has helped to mute those protests.
