Local officials say the students were returning home after taking part in the university entry test in Paroun, the province capital, late Friday afternoon.
The students reportedly came from Nangaraj High School of Noorgaram District. The incident also left three other students wounded.
Nooristan is one of the remote provinces of Afghanistan where locals complain that government has not paid attention to the reconstruction.
Most of its bridges are still the old ones in damaged condition. Only few roads have been paved in Nooristan and most of its highways are still dust roads.