Police were first on scene and found smoke coming from the second and third floors of 332 West Oak Street and reported a working fire.
As fire crews arrived on scene a second alarm was issued calling in additional personnel from around Schuylkill County.
The fire was brought under control within the hour but damaged the homes at 332, 330, and 328 West Oak Streets.
As a result of the fire, 6 people were displaced.
Shenandoah Fire Marshall Rick Examitas reported on Sunday that an investigation led to the finding that the fire started in the basement of 332 and was electrical in nature. The fire was officially ruled accidental.