Life sentences in the North African country translate to 25 years in jail.
The defendants were accused of setting a church on fire in August 2013 in the Kerdasa area, which is largely inhabited by Islamists.
In the ruling on Tuesday, the court also fined the defendants 20,000 Egyptian pounds (US$1,119) each.
They were charged of joining a banned group, possessing weapons, blocking the road and disturbing the public order, according to the prosecutor.
Egypt has been experiencing anti-security attacks since the army-led ouster of the Islamist leader Mohamed Morsi in 2013, and ban of his Muslim Brotherhood as terrorist in 2014.
Thousands of Islamists were detained and hundreds were facing trials. Morsi and prominent figures of his group have received final verdicts that varied from death to life sentences over accusations of murder, violence and spying.