Colwyn Baker, David Hennessy and Nigel Putman are accused of 49 counts of abuse against 24 boys at the now-defunct Swaylands School in Kent.
Maidstone Crown Court heard children abused at the school "were positively encouraged to abuse other pupils".
The men have denied carrying out sex assaults.
They are accused of preying on children from 1963 to 1993 while they were residential child care officers at the school in Penshurst.
Prosecutor Philip Bennetts QC said: "Abuse and the age of pupils abused led some pupils to consider that there was nothing wrong with abusing other pupils."
Swaylands School, which catered for boys with emotional and behavioural difficulties, closed in 1993.
Mr Bennetts said one boy was so scared of Mr Baker he often stayed awake or slept in stairwells, and another boy was abused by him almost nightly for three years.
He said one boy told investigators he resisted Mr Baker for a long time but eventually caved in after the defendant made sure no-one spoke to him.
Another alleged victim said he was abused on his first or second night by Mr Hennessy who told him: "It's not worth crying, it won't help you."
Mr Baker, 71, of Craighouse Avenue, Morningside, Edinburgh, faces 24 indecent assault and three serious sexual assault charges.
Mr Hennessy, 74, of Westfields, Narborough, King's Lynn, Norfolk, is accused of 17 indecent assault charges, one of gross indecency with a child, and one serious sexual assault.
Mr Putman, 62, of Kings Road, Slough, Berkshire, is accused of three indecent assaults.
The jury was told Mr Baker was convicted in 1994 of four counts of indecent assault on a boy and one of gross indecency.
Mr Bennetts also disclosed Mr Hennessy was convicted in 1993 of four counts of indecent assault on a boy and two sex offences against a pupil.
The trial was adjourned.
Three men sexually assaulted boys for more than 30 years at a school for vulnerable children where abuse was "almost the norm", a court has heard.