Publishing her findings, former judge Lady Smith said the school had “failed to look at itself through a realistic and critical lens” for decades.
“It is clear it was assumed that abuse did not and would not take place,” she said.
“When it did, the school could not accept that it had happened, failed to address it, and failed to recognise the risk of it continuing. Complacency was the order of the day.
“When complaints were made, they were either disbelieved or left unresolved. Staff chose not to notice and avoided intervention or investigation despite there being obvious signs of abuse.”
The report names two long-serving members of staff as perpetrator of abuse: Hamish Dawson, a housemaster and senior school teacher, and John Brownlee, a housemaster and deputy head of the junior school.
It also singles out prep school teacher Iain Wares, who went on to abuse pupils at Fettes College and is currently awaiting extradition from South Africa; and physics teacher William Bain, who has twice been convicted of sex offences.
He began his lengthy history of abuse at Edinburgh Academy before moving on to harm children in other schools.