Headteachers have admitted that the stress of work has caused them to crash their car, exclude children unnecessarily and miss deadlines for bids for extra cash for their school.
The report, from Keele university, shows that more than 10 per cent of heads admit to such errors, suggesting that as many as 2,500 schools in England and Wales could be affected.
The survey of 688 heads also reveals that a third said work made them too tired for sex, a quarter said work had affected their relationship, and almost a 10th said it played a part in the breakdown of their relationship.
The anonymous survey details the mistakes, including four who admitted they had excluded pupils unnecessarily.
One said they had expelled a pupil wrongly because of pressure from parents. Another said their error had been the "exclusion of a child when really the incident should have been better handled by me".
Others said they had placed pupils in the wrong year groups, failed to gain money for their schools by missing deadlines for bids, and lost their temper with staff, parents and pupils through sheer tiredness.
Eight in the sample said that they had either been involved in car crashes - or only narrowly escaped them - because of exhaustion or stress.
One head admitted to falling asleep at the wheel, and others to driving backwards into fences, and scraping the school gates.
Brendan Hassett, head of Dolphinstone primary in Lancaster, said he nearly crashed while driving home from work in October because of stress.
"I pulled over and there were tears flooding down my face," he said. "I was crying uncontrollably. I felt like I was going under. I could have crashed into the back of something and my wife would have lost her husband, and my two children their dad."
Mr Hassett said an overload of Government initiatives, including introducing compulsory planning time and new management payments for his staff, had left him feeling more stressed than he had felt throughout his 20-year career. He also teaches for 70 per cent of his timetable.
One head admitting to hiring what proved to be an unsuitable member of staff in a hurry before an Ofsted inspection.
"This person had two different affairs with two different parents and this led to a family break-up," she said.
"Altogether we lost 12 children out of a school population of 70. His actions severely damaged the school's reputation over several years."
Another said that their chief error had been "not informing parents when their child had been assaulted by another pupil".
A third admitted to leaving a child protection referral to the following day.
"This might have had serious consequences but in fact did not."
Another said: "On speech day I missed some girls out when reading the list of prize-winners. They and their families in the audience were very upset."
Mick Brookes, general secretary of the National Association of Head Teachers, which commissioned the report, said the mistakes illustrated the dangers of increasing heads' workloads.
Mr Brookes said that mistakes he had made as a head in Lincolnshire in the 1980s included snapping angrily at a parent who wanted information about a school trip, only to discover that she was on the governing body and recruiting panel of a school where he later applied to work.
The survey also found that 94 per cent of heads had experienced work-related stress, and that 61 per cent felt their work affected their family and private life "all or almost all of the time".