The strike hit a group of people outside a mosque in the southern city of Khan Yunis, emergency services spokesman Ashraf al-Qudra told AFP, adding that three of the dead were from the same family.
One woman was among those killed, Qudra said.
The deaths took the toll from an Israeli operation to 303, many of them women and children.
One Israeli civilian and one Israeli soldier have been killed since the campaign started on July 8.