Fire Chief John Ballard said firefighters received the call just after 7 a.m.
“When they arrived, there were flames coming out of the window and front door,” said Corky Brown, Cedar Hill Public Information Officer.
One victim was pronounced dead at the scene, while the other two were rushed to a local hospital and died later.
Victims have been identified as Larry and Lillian Pitts, and their son Ronald Earl Thomas.
According to Cedar Hill Fire Marshal Randy Jordan, an investigation as to the cause of the fire is ongoing.