A roof scaffolding system includes a support assembly disposed on one inclined surface of a roof extending to a peak of the roof and attached to an opposite inclined surface of the roof near the peak thereof, a roof jack resting on the one inclined surface of the roof astraddle and connected to the support assembly, a valley support assembly disposed on a valley of the roof along one side of the one inclined surface and extending to the peak of the roof and attached to the opposite inclined surface of the roof near the peak thereof, and a valley jack astraddle the valley of the roof and valley support assembly and anchored to the valley support assembly. The roof and valley jacks are spaced apart so as to support a flat board extending therebetween.