[1] It was held on 23 March over a distance of 203 kilometres (126.1 miles) and was the sixth race of the 2012 UCI World Tour season.

E3 Harelbeke was held as a UCI World Tour event for the first time,[2] after previously being held as a 1.HC race on the UCI Europe Tour.

[3] As well as its promotion to the World Tour, the race moved to a Friday running from a Saturday; the move was in order to give riders a day's break prior to the following World Tour event, Gent–Wevelgem.

[4] In a mass sprint finish, the race was won by Omega Pharma–Quick-Step rider Tom Boonen,[5] who in the process, became the most successful rider in the history of the race; his fifth victory – after four previous victories in succession between 2004 and 2007 – in Harelbeke took him beyond the record tally of four victories that he had been sharing with fellow Belgian rider Rik Van Looy.

Seven other squads were given wildcard places into the race,[8] and as such, formed the event's 25-team peloton.