The Holiday Inn Express in Picardy Place was put up for sale in November after its Aberdeen-based owners, the European Development Company (EDC), ran into financial difficulties.
It was bought by International Hotel Properties Limited (IHL) for £17.7m, plus costs.
The property takes IHL's portfolio to nine hotels.
The sale was announced by administrators from FRP Advisory.
The Grade B listed building consists of 161 rooms and has planning permission for a 20-bedroom extension at the rear of the property.
FRP said it was continuing to operate two other hotels in Aberdeen which were also placed under administration following EDC's collapse.
The Holiday Inn in Westhill and Holiday Inn Express on Chapel Street will be placed on the market "shortly", the administrators said.
Joint administrator Iain Fraser added: "Trade has been firm over the festive period and the administration of EDC represents a rare opportunity to acquire quality hotels in Aberdeen in busy locations.
"We would therefore encourage interested parties to contact the Aberdeen office of FRP Advisory as soon as possible."
A prominent Edinburgh hotel has been sold by administrators in a multi-million pound deal.