The neighbor tells ABC7 News her dog alerted her that the house next door on the 7200 block of Lavonda Court was on fire.
"I went and banged on their door and told them that the house was on fire," the neighbor said. "And then the neighbor across the street came over, knocked on their door, and they rushed out of the house and went across the street. I'm just glad the dog was pacing like she was."
The family of three was able to safely escape the home. The Red Cross is assisting them.
When firefighters arrived, they found flames coming from the attic of the two-level split foyer home, officials said. It took 40 firefighters about 90 minutes to extinguish the blaze, which was wind driven.
Prince George's Fire officials said one firefighter suffered second degrees burns while battling the blaze.
The cause of the fire is under investigation. The total loss is estimated at approximately $150,000 for the structure and its contents.