The majority of teachers have considered leaving the profession in the last six months, a survey has found.
Three-quarters (76%) said the workload gave them doubts, with a quarter (24%) saying they thought about packing it in because they dislike the culture of schools.
Three in 10 (29%) said they do not feel they get enough support while 27% said poor pupil behaviour was putting them off.
Being unhappy with the quality of leadership and management (43%) and insufficient pay (43%) were also heavily cited as reasons.
The poll of both primary and secondary school teachers found 59% had thought about quitting, with much-needed science teachers among those most likely to have considered doing so (67%). Only art and drama teachers were more likely (75% and 69% respectively), but these were far less statistically significant as only a handful of teachers questioned did these subjects.
The findings are based on a YouGov survey of more than 1,000 current teachers in England, focus groups and interviews.
Teachers said they primarily stay in teaching when they feel they are having an impact, with 92% saying the opportunity to make a difference in children's lives was an important motivation.
The report commissioned by education company Pearson UK and think tank LKMco also identified four overlapping teacher types, which it said could help policy makers, educationalists and school leaders better understand the school workforce.
These are practitioners - teachers who are particularly motivated by a love of their subject and a desire to teach children, and make up around a fifth of teachers.
Around a third are idealists who want to make a difference to society, while moderates make up a quarter of the profession and are moderately influenced by a broad range of factors.
Just over a fifth of teachers are rationalists and tend to carefully weigh up a combination of pragmatic, personal and social justice-related factors.
Pearson UK president Rod Bristow said: "This research points to a simple conclusion: teachers want to make a difference for our children; when they feel they can't for whatever reason, we risk losing them from the profession.
"We need nothing less than a call to action to give them the support they need to make that difference. The Government is taking the issue of teacher supply and retention seriously.
"But the larger conversation about what inspires teachers to join - and stay - in the profession will require hard talking in Whitehall, in teacher training institutions, and in every staff-room across the country."
Christine Blower, general secretary of the National Union of Teachers (NUT), said: "This latest report bears out what NUT surveys have found. Teachers love their jobs but the profession has become so unattractive and unworkable that more than half of teachers are considering leaving the profession.
"Endless pontificating on the merits of academies and free schools, alongside the energy and money that is ploughed into flogging this dead horse need to stop.
"Parents, carers, children and teachers all deserve better. Teacher morale is low, curriculum and examination reforms have left schools with a stifling syllabus, while the over-testing of children from the age four upwards is taking the creativity and joy out of learning and teaching.
"Nicky Morgan needs to wake up to the fact that it is her Government's policies that have created this crisis of teacher recruitment, retention and morale."
Labour's shadow secretary of state for education, Lucy Powell, said: "The Tories are overseeing a teacher shortage crisis in this country which is threatening standards in our schools.
"An increasing proportion of maths, science and English lessons are being taught by teachers without the relevant qualifications; we're seeing falling applications into teaching and the highest number of teachers leaving the profession on this Government's watch.
"Worryingly, as this report shows, more than half of teachers have considered leaving the profession in the last six months. The Government are in danger of failing to deliver an excellent education for all children if they don't recognise this pressing issue and get a grip."
A Department for Education spokesman said: "This report shows why teaching continues to be such a popular career, with nine out of ten teachers relishing the chance to make a difference in young people's lives. Latest figures show the highest number of people joining the profession since 2008 and the rate of former teachers coming back to the classroom has continued to rise year after year - from 14,720 in 2011 to 17,350 in 2014.
"While the vast majority of teachers stay in their roles for more than five years, we know unnecessary workload can detract from what matters most: teaching.
"That's why we launched the Workload Challenge, and are working with the profession to understand and tackle the top issues that teachers said caused the most bureaucracy, with leading education experts taking action on key areas such as marking and lesson planning."