Six people were treated for smoke inhalation - with one of them taken to hospital - after the fire at Arnold Clark on Girdleness Road in Torry.
The emergency services were alerted to the fire at about 05:00. The road was closed between Wellington Road and Old Church Road as a result.
A number of nearby flats were evacuated due to the heavy smoke.
Aberdeen City Council later said the residents who had to leave Girdleness Road, Girdleness Terrace and Kirkhill Road had been allowed to return home.
More than 50 firefighters have been involved in the incident.
Residents have been taken to the community centre on Balnagask Road.
Arnold Clark said in a statement: "We are aware of serious damage to the site and we are working to establish the full extent of this.
"It is our absolute priority to help all customers who had cars on site to be mobile again by offering a replacement courtesy car on a like-for-like basis where possible.
"We understand this is a hectic time of year and we are doing all we can to minimise the inconvenience to those affected, and we are working to reduce any disruption to the local community."
The statement added: "The branch is currently closed, however, we will endeavour to transfer all appointments to our surrounding sites. At the moment an investigation is taking place and we will provide an update in due course.
"Our staff will contact customers today if their car has been affected and will arrange a temporary replacement vehicle by the end of today. In the meantime, customers with any questions can contact our Customer Services department on 0141 305 8328."
The Scottish Fire and Rescue Service said they attended a "well-developed" fire in the workshop area of the premises. The fire has affected the sales building.
A spokesman said: "Firefighters are aware that there are oil tanks and acetylene cylinders involved in the fire, therefore the evacuation was deemed necessary to ensure public safety. There are also around 100 tyres involved in the fire.
"Due to the severity of the fire and risks, crews were forced to withdraw and fight the fire externally to ensure firefighter safety."
An Aberdeen City Council spokesman said: "Aberdeen City Council's Care for People Plan swung into action this morning. Balnagask Community Centre was opened to receive residents affected by the smoke from the fire and the Red Cross was on hand to provide support for families.
"Our housing support staff have been on site to provide information and support, while social work colleagues have also been providing information for any vulnerable people requiring extra support."
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About 80 people had to be moved to a community centre in Aberdeen due to a major fire at a car service centre.