3 in 10 teachers suffer false misconduct claims.
Nearly 3 in 10 teachers have faced false allegations of misconduct from pupils, according to a poll published on Monday.
The survey for the Association of Teachers and Lecturers found that 28% of staff had faced allegations that later proved to be groundless.
Mary Bousted, the union's general secretary, said false claims blight teachers' career, private lives and health.
"It is time the balance was redressed so that school staff are not presumed guilty until proven innocent," she said in a statement. "We are losing good teachers, heads and support staff to the detriment of children's education."
The authorities should also consider allowing staff under investigation to remain anonymous to make it easier for them to resume work if the claims do not stand up.
The survey of 1,155 teachers and support staff in private and state schools found that half of the allegations were immediately dismissed. Police were involved in 16% of the cases. They took no action in 55 of the 67 those cases.
The union, which has 160,000 members, said staff are at risk of malicious claims by a handful of pupils that are then copied by other children.
An anonymous teacher from Wales, who is head of a department at his school, said he faced a false allegation after reprimanding a pupil for being late.
"Although the allegation was bogus a record of the allegation would be made and kept on my personnel file," the teacher said."
A primary school teacher said she had not been back to work since being accused by a parent of hitting their child.
"I had post traumatic stress and a period of long-term sick," the teacher said.
A separate poll for the same union in April found that nearly half of staff had considered leaving the profession because of pupils' increasingly bad behaviour.
A fifth said they had suffered mental health problems due to the stress of coping with their pupils.