The incident took place in the northern city of Qena, long known as the heart of the nation's illicit arms smuggling trade. Officials said the number of guns coming from neighboring Libya has increased dramatically since that country's uprising began in 2010.
Police said Omar el-Hambool walked into a classroom and shot a student after what police described as a previous dispute, Ahram Online reported.
The incident occurred the same day a student in the Nile Delta region launched a tear gas canister into his school after finding it discarded on the street. Police said the boy did it "for fun."