This incident marks the second in two days that a school has been struck by Israeli forces.
An Israeli warplane targeted the UN-run Asma School in the Al-Shati refugee camp, according to Palestinian Civil Defense spokesman Mahmoud Basal.
He confirmed that the attack resulted in three deaths and 15 injuries, some critically.
On Thursday, at least 40 displaced Palestinians were killed in an Israeli airstrike on a school sheltering thousands of displaced people in the Nuseirat refugee camp in central Gaza.
Israel has continued its brutal offensive on Gaza since an attack by the Palestinian group Hamas last Oct. 7, despite a UN Security Council resolution demanding an immediate cease-fire.
Some 36,700 Palestinians have since been killed in Gaza, most of them women and children, and over 83,500 others injured, according to local health authorities.
Eight months into the Israeli war, vast tracts of Gaza lay in ruins amid a crippling blockade of food, clean water, and medicine.
Israel stands accused of genocide at the International Court of Justice, whose latest ruling ordered Tel Aviv to immediately halt its operation in the southern city of Rafah, where over a million Palestinians had sought refuge from the war before it was invaded on May 6.