The family of Harvey Willgoose say the schoolboy "would still be alive" if his school hadn't missed "many opportunities" to protect him.
Harvey, 15, was stabbed outside the canteen at All Saints Catholic High School in Sheffield last year by a fellow pupil.
On the one-year anniversary of their son's death, Mark and Caroline Willgoose say they have been "devastated" by a new report into "chances missed" by Harvey's school to assess the risk his killer posed.
Mohammed Umar Khan, also 15 at the time of the attack, had brought a 13cm hunting knife into school on the day he fatally stabbed Harvey.
He was sentenced to life with a minimum of 16 years in prison following a trial at Sheffield Crown Court.
'Harvey deserved better'
But an independent review, commissioned by the school itself, revealed school failures in the months leading up to Harvey's murder, including:
Speaking at a news conference in Sheffield, Harvey's mother Caroline Willgoose said: "Reading the findings of this report has been devastating.
"To see in black and white the chances there were to step in, the signs that were missed and how many opportunities there were to protect my boy is something I'll carry with me for the rest of my life.
"Harvey deserved better."
'No other family' should go through this
Mark Willgoose said they have had "no apology" from the school, following the publication of the report.
"We would like one," Ms Willgoose added.
The report has only been shared in abbreviated form with the media, but a full copy has been shared with Harvey's family.
They called on the school's trust, St Clare Catholic Multi Academy Trust, to publish the report in full for "transparency" and so lessons can be learned by them and all schools.
Ms Willgoose said: "No other family should have to sit in court listening to how their child was killed, or have to read a report that lays bare how their child could have been better protected."
School has introduced 'robust measures'
Sky News contacted St Clare Catholic Multi Academy Trust for comment.
In a statement, chief executive Steve Davies said: "Harvey's death was a profound tragedy for our community and our thoughts remain with his family.
"It is clear that the report identifies areas for improvement, including in relation to our processes, information-sharing, and training."
He added the school had "already implemented a number of robust measures over the last year".
The report also outlined 10 recommendations, including mandatory record-sharing at the outset of any pupil school move, a clear weapons-response policy and national guidance on how schools respond to knife possession and reports of knife possession.
A Department for Education spokesperson told Sky News it will "reflect on the report findings".
It encouraged "all schools to do the same".
(c) Sky News 2026: 'Harvey deserved better': Family say school missed opportunities to protect murdered schoolboy
Epstein files: Police reviewing misconduct claims after Mandelson accused of leaking sensitive information
Sarah Ferguson's charity to close after Epstein revelations
Dragons' Den star Jones tees off with takeover of American Golf
Denmark has become a cancer pioneer - this is why UK is lagging behind
Resident doctors vote to continue industrial action for another six months