A US survey of more than 7,000 LGBT students has suggested that the vast majority are harassed at school for their sexuality or gender identity.
The national survey found that 84 per cent were verbally harassed and 18 per cent were physically attacked for being gay, lesbian or bisexual.
The data was collated from the 2009 National School Climate Survey by the Gay, Lesbian and Straight Education Network (GLSEN). It surveyed 7,261 LGBT students between the ages of 13 and 21 from across the US.
GLSEN also found that 61 per cent of LGB respondents felt unsafe at school, while 62 per cent did not report bullying to teachers because they feared nothing would be done or the problem would get worse.
Sixty-three per cent reported being bullied for their gender expression, while 12.5 per cent said they were attacked for not acting masculine or feminine enough.
The results suggested that homophobic bullying was likely to result in students having higher rates of absenteeism, as LGBT students who said they felt unsafe were three times more likely to have missed classes in the last month compared to the general student population.
Students who frequently suffered homophobic bullying had grade point averages almost half a grade lower than students who were rarely harassed and were less likely to express ambitions to go to university.
Depression and low self-esteem were also more common in those bullied over their sexual orientation.
However, the survey found that Gay-Straight Alliances had positive effects for gay student, with lower rates of victimisation and homophobic remarks. However, less than half of students questioned said their school had such a club.
GLSEN executive director Eliza Byard said: "In 1999, GLSEN began data collection on the school experiences of LGBT students in order to fill a critical void in our knowledge and understanding of the ways LGBT issues play out in schools. It could not be clearer that there is an urgent need for action to create safe and affirming schools for LGBT students.
"As our nation seems to finally be taking bullying more seriously, it is crucial that LGBT students are no longer left out of efforts to address this public health crisis."