More than a third of teachers say a colleague in their current school has been the victim of a false allegation by a student, according to a survey by the ATL union.
Over a fifth of teachers say a malicious accusation has been made by a pupil's parent or family member, the poll adds.
The figures have prompted the union to demand that the government grant teachers and college staff anonymity until they are charged, in order to protect their reputation.
The survey from the ATL, which hosts its annual conference in Liverpool this week, reveals that, of the most recent allegations, half were dismissed by the school or college.
Respondents said the number of false allegations being made was on the rise, owing to pupils taking exception to being told off by staff.
A state secondary teacher in Worcestershire said: “After 22 years in teaching I feel very vulnerable now, as pupils twist things that are said and make serious comments – they do not see the serious manner of their allegation when in fact it is their behaviour we are challenging.”
David Guiterman, the ATL’s branch secretary in Cornwall, who has proposed a debate on the length of time it takes to resolve an allegation, said: “Even if the allegation is shown to be false it leaves a lasting scar. In a local case, a member decided to resign even though the allegation was shown to be false. He did not want to carry on lecturing.”
The figures are based on responses from more than 630 school and college staff across the UK.
Mary Bousted, the ATL’s general secretary, said innocent staff needed to be protected from having their careers and lives “irretrievably damaged by a false allegation”.
“We call on the police and local safeguarding boards to work harder to resolve cases and to protect the rights of education staff,” Dr Bousted said.
“And we call on the government to change the law to give all education staff the same rights to anonymity until charged – without this, innocent teaching assistants, school librarians and lab technicians, as well as assistants, lecturers and managers in further education, risk having their lives blighted unnecessarily.”