Driver Harry Clarke lost consciousness behind the wheel and the vehicle careered out of control on 22 December 2014.
Erin McQuade, 18, and Jack and Lorraine Sweeney, 68 and 69, from Dumbarton, Stephenie Tait, 29, and Jacqueline Morton, 51, both from Glasgow, and Gillian Ewing, 52, from Edinburgh, were killed.
The service is being organised by Glasgow Churches Together which represents the main Christian denominations in the city.
Scotland's First Minister Nicola Sturgeon will lead the mourners at the event which is open to the public.
Around 700 people are expected to attend and will be welcomed by the cathedral's minister Revd Dr Laurence Whitley.
Catholic Archbishop Philip Tartaglia will lead prayers at the service.
Chaplain to the Scottish Fire and Rescue Service, Fr Jim Thomson, will attend the event.
He told Premier: "I think it's very important that we remember that terrible tragedy that happened last year.
"We remember the people involved and we do what we can to try and give some comfort and support to the families that were involved.
"They'll still remember the terrible incident.
"I think there will be a sadness about the city as they remember what happened there and they'll want to support those left behind and those who were injured."
A spokesman for Glasgow City Council said the Christmas attractions in George Square will be restricted on the day of the anniversary.
Bookings for the ice rink will not be taken between 2pm and 3pm, while rides will be shut down between 2.15pm and 2.45pm, covering the time when the crash occurred.
Refuse collection vehicles will also be kept out of the square and the immediate vicinity, and limited as much as possible in the city centre.
Those who wish to leave floral tributes or pay their respects are urged to do so at the Gallery of Modern Art in Royal Exchange Square.
Driver Harry Clarke lost consciousness at the wheel but a fatal accident inquiry found the crash might have been avoided if Mr Clarke had told the truth about previously blacking out at the wheel.
Sheriff John Beckett QC made a total of 19 recommendations, including calling on Transport Secretary Patrick McLoughlin to hold a consultation on whether doctors should be given more freedom to report fitness-to-drive concerns directly to the DVLA.
