The Houston Fire Department responded to the fire at 3233 Mangum Road near West 34th around 2 a.m. Wednesday.
In an update just before 4 a.m., they said the fire had been extinguished.
Officials said a building with five units was impacted -- four units had fire damage and one unit had smoke and water damage.
No residents were injured and were all able to self-evacuate, HFD said.
One firefighter was transported to a nearby hospital for dehydration. Video from the scene showed the firefighter on a stretcher.
Officials were still investigating what sparked the flames.
The Red Cross has been contacted to assist the displaced residents.