Dalawna Berran-Lett, 33, of North Braddock, pleaded guilty to two counts each of involuntary manslaughter, endangering the welfare of children and recklessly endangering another person, the Pittsburgh Tribune-Review reported.
The charges stem from a January 4 incident in which Berran-Lett's sons, Ky'heir and Dy'heir Arthur, were left home alone and their home burned down.
Police said they believe the boys were trying to cook food while their mother stepped out to buy marijuana.
The mother told police that she locked the boys inside the home at 2:45 p.m. to find her 15-year-old daughter, Mariah, whom she suspected of stealing her marijuana. A passerby reported the fire at about 3:30 p.m.
Berran-Lett will be sentenced by Allegheny County Common Pleas Judge Edward Borkowski on Feb. 27.