The four members of the Zuweidi family, including two girls, were killed on Saturday in Beit Hanun, where a fifth person was also killed in a separate air strike, emergency services spokesman Ashraf al-Qudra said.
Qudra named the members of the Zuweidi family as Mahmud, 23, Dalia, 37, and two girls aged six and two.
A 25-year-old woman was also killed in an Israeli air strike in central Gaza's Deir al-Balah, raising the death toll in 12 days of Israeli aggression against Gaza to 324.
More than 2,200 others have been injured since the Israeli deadly offensive began on July 8.
The United Nations says the number of displaced people of Gaza has almost doubled over the past 24 hours. More than 40,000 Palestinians are now homeless.
RA/SHI