Vancouver Police said the fire started on the ground floor of the building in the 700 block of Main Street at around 6:30 a.m. PT.
Firefighters quickly extinguished the fire, and damage was limited to the ground floor.
A 56-year-old Vancouver man suffered smoke inhalation but his injuries are not life-threatening, police said.
Authorities said the cause of the fire does not appear to be suspicious.
Vancouver Police spokesperson Sgt. Randy Fincham said social services were called in to help find appropriate housing for those displaced by the fire.
“We know how important it is for these people to have a warm, safe place to stay over the holidays,” he said.
Fincham said 18 people have lost their rooms in the London Hotel.
The London Hotel normally provides 73 non-market housing units.