The mother was injured and was transported to an area hospital, a Lincoln County 911 dispatcher said.
The names of the victims weren't immediately available.
The blaze broke out around noon in a two-story apartment building in the Harts area, said Assistant Fire Chief David Adkins with the Harts Volunteer Fire Department.
A preliminary investigation indicates the cause may have been electrical. The state Fire Marshal's office is assisting in the investigation.
Five children have been killed in West Virginia fires in the past week.
One of those, an early morning blaze in Charleston on Feb. 19 in which two children were killed, has been ruled an arson.
Specific details about the cause of the fire haven't been released. Charleston Police Sgt. S.A. Cooper, who is assisting the state Fire Marshal's office in the investigation, said Friday that a person of interest had been identified but no arrests had been made.
Addison Neely, 7, and Andre Neely, 4, were killed in the fire. Their father and an older brother were injured.
Later that morning, 17-month-old Tyler Whited died in a South Charleston apartment fire. That blaze was determined to be an accident.
