Investigators, who released a summary of the report late Monday, say that seven "incidents" killed dozens of people sheltering in UN installations.
It holds Israel's army responsible for all of them, but also condemns Palestinian militants for storing weapons in and even launching attacks from the vicinity of some UN buildings.
Below are the report's verdicts on two of the deadliest incidents.
July 24: Beit Hanun primary school
The area surrounding the school in Beit Hanun in northern Gaza was the scene of fierce fighting and the school had been turned into a shelter for displaced Gazans.
In the days before the incident, the UN agency for Palestinian refugees (UNRWA) received "multiple calls" from Israel saying rockets were being fired from the school and its immediate vicinity, and that it should be evacuated ahead of an Israeli military response.
Witnesses said there was no militant activity in the area.
UNRWA tried to obtain from Israel a "window of opportunity" to evacuate the school's occupants, but none was granted.
The 450 people in the school on that day refused to evacuate, and at 3:00 pm two mortar rounds hit, one in the courtyard and another in front of the entrance, killing "between 12 and 14" people and injuring 93.
July 30: Jabaliya girls' primary school
The UNRWA school in Jabaliya refugee camp in northern Gaza was one of dozens of schools used as a shelter, and housed 3,000 people.
In the days before the incident, fighting raged in eastern Jabaliya and the army asked residents to evacuate the area.
Witnesses said there was no militant activity in the school or its immediate vicinity, and that weapons were strictly prohibited inside the facility.
"This rule was strictly observed," the report said, citing witnesses.
At around 4:45 am, four artillery shells hit the school, killing 17 or 18 people, the report said. Some 99 people were wounded.
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"No prior warning had been given" by Israel, it said.
Israel is investigating both this and the July 24 incidents.
In a separate incident, a drone strike killed 15 people at a UN school in Rafah in southern Gaza on August 3.
Israel says it was targeting three militants riding a motorbike, but had been unable to call off the strike when it became apparent it would land next to the school.
Did militants hide arms in UN schools?
In three cases examined by UN investigators, Palestinian militants used vacant UN schools to hide weapons such as mortar tubes and ammunition, and in two or three cases fired at soldiers from the sites.
What about reaction to the report?
The Islamist movement Hamas, which was fighting Israel, said it proves that the Israeli military "committed war crimes against Palestinian civilians", and denied knowing anything about weapons stored at UN schools.
Israel said the report confirms militants used UN installations for their activity. It says it also showed Israel has cooperated with the investigation and is conducting its own probes.
UN Secretary General Ban Ki-moon has slammed both sides.
"I deplore the fact that at least 44 Palestinians were killed as a result of Israeli actions and at least 227 injured at UN premises being used as emergency shelters," he said on Monday.
"The fact that they (schools) were used by those involved in the fighting to store their weaponry and, in two cases, probably to fire from, is unacceptable."
What happens next?
The report will not lead directly to legal action by either side, but the Palestinians are threatening to sue Israel for alleged war crimes through the International Criminal Court.
The investigation serves mainly to illuminate some of the most controversial events during the war, which killed about 2,200 Palestinians and 73 on the Israeli side.