10-year-old Demiana Victor, who was injured in the Botroseya church bombing on December 11, died of her injuries at Al-Galaa Military Hospital on Saturday, bringing the death toll of the blast to 29.
Victor is a ninth grade pupil at Notre Dame des Apotres school, and the eldest among her brothers.
The funeral will be held at Botroseya church in Abbasiya at noon on Sunday.
The "Islamic State" terrorist group claimed responsibility for the bombing attack at Cairo's largest Coptic cathedral that killed 29 people and injured 45 others.
Many of the victims were women and children attending Sunday mass, in the deadliest attack on Egypt's Christian minority in years.
The explosion took place in Botroseya church, which adjoins St Mark's, Cairo's main cathedral and the seat of the Coptic Pope Tawadros II, where security is normally tight.
Edited translation from Al-Masry Al-Youm