Deaf children are being "left behind" in Scottish education, the National Deaf Children's Society has said.
Its analysis suggests deaf pupils are eight times more likely to leave school with no qualification than their hearing classmates.
The charity also found that only 29% of deaf school-leavers go to university. The figure for hearing students is 45%.
The Scottish government said it is committed to giving all young people the support they need.
The society has called for action to address the achievement gap, including the introduction of a bursary to train specialist teachers.
It said nearly a third of specialist teachers for deaf pupils had been lost over the past eight years.
Alasdair O'Hara, the head of the charity's campaign in Scotland, said: "Deaf children arrive at school with amazing potential only for many to be left behind.
"While some are achieving excellent results and going on to their dream jobs, these results show that many more are being let down by the education system they rely on.
"We know that every deaf child can thrive at school if they receive the right support, but until the funding for that is put in place, many will continue to struggle."
He said the system is failing "despite the best intentions" of the government.
"The Scottish government must act quickly by investing in deaf education," he added, "and introducing a bursary to ensure that the right support is available in our classrooms.
"Every child deserves the chance to shine at school, and deaf children are no exception."
A Scottish government spokesman said: "We want all children and young people to get the support that they need to reach their full learning potential, including those with sensory impairments.
"The Additional Support for Learning Act places education authorities under duties to identify, provide for and review the additional support needs of their pupils.
"The Scottish government provides over £500,000 to voluntary sector organisations to support children and young people with sensory impairment and £150,000 to the Scottish Sensory Centre to support training to increase the capacity of staff in schools to provide effective support to pupils with a sensory impairment."