Librarians are the most unhappy with their workplace, often finding their job repetitive and unchallenging, according to psychologist Saqib Saddiq.
He will tell the British Psychological Society that one in three workers suffer from poor psychological health.
The study surveyed nearly 300 people drawn from five occupations.
They were firefighters, police officers, train operators, teachers and librarians and were intended to cover the spectrum, with the librarians first-thought to be the least stressful occupation.
The research, being presented at a society conference in Glasgow, looked at nine "stressors", such as how much control workers thought they had over their working day, their workload and how much they earned.
It also looked at absenteeism, job satisfaction and whether work stress spilled over into their private life.
Librarians complained about their physical environment, saying they were sick of being stuck between book shelves all day, as well as claiming their skills were not used and how little control they felt they had over the career.
They were also more likely than other professions to be absent from work.
Mr Saddiq urged all employers to tackle the problem of stress.
"Although these findings seem strange at first, they actual show how insidious stress can be, and how it can have an unhealthy impact in any organisation," he said.
"Firefighters and police are trained to deal with the stresses that their jobs undoubtedly entail; librarians and school teachers are less likely to have these support systems in place.
"In addition, stress impacts different personalities in different ways, and different personalities may be drawn to different roles."