Nearly half the allegations made against teachers in England are malicious, unsubstantiated or unfounded, a government study suggests.
According to the Department for Education survey, only 3% of investigations resulted in a criminal caution or conviction for the teacher.
Schools Minister Nick Gibb said the research justified the government's plan to give teachers a legal right to anonymity when pupils made claims.
One union said it was "a small step".
The survey, commissioned by the Department for Education, looked at the number and nature of abuse allegations referred to 116 English councils between April 1 2009 and March 31 2010.
Of 12,086 allegations referred, 2,827 (23%) were against school teachers, and 1,709 were against non-teaching staff in schools.
It found that 47% of all allegations made against teachers, and 41% against non-teaching staff members were found to be unsubstantiated, malicious or unfounded.
About 18% of teachers and 29% of non-teaching staff were suspended while accusations were investigated.
Based on information held by councils rather than the police, the survey found that 12% of the accused teachers and nearly a fifth of those non-teaching members of staff faced a criminal investigation.
And just 3% of concluded investigations against teachers resulted in a criminal caution or conviction, with the figure 5% for non-teaching staff, the survey found.
The government plans to allow teachers anonymity when facing allegations from pupils - up to the point they are charged with a criminal offence.
'Damage is done'
Schools Minister Nick Gibb said: "Every allegation of abuse must be taken seriously, but some children think they can make a false allegation without any thought to the consequences for the teacher concerned. When these allegations are later found to be malicious or unfounded, the damage is already done.
"We will back teachers as they seek to maintain discipline in schools and raise academic standards."
The general secretary of the NASUWT teaching union, Chris Keates, said the government's plans were a "small step in the right direction" but needed to be expanded.
"In addition, it doesn't address the issue of information being kept by police even when a teacher has been exonerated," she added.