The National Deaf Children’s Society say more needs to be done for young people in Devon.
It's after a critical report by Ofsted, which says the 800 youngsters in the county need better support.
The report found: "The local area has been too slow to implement the 2014 SEND (special educational needs and disability) reforms.
"As a result, too few children and young people have an education, health and care plan that meets their needs and aspirations.
"This situation has caused, and continues to cause, distress and upset for parents and carers, and frustration for frontline staff in schools and colleges."
"Too many of the plans have gaps in the provision and support, particularly to meet the health and care needs of children and young people with SEND.
"Intended outcomes are vague and not precise enough for schools, colleges and settings to be able to use this information to plan their work with children and young people."
Sarah Collinson, South West Regional Director at the National Deaf Children’s Society, said: "This report paints an incredibly worrying picture.
"In our county, there are nearly 800 deaf children, and each and every one has so much potential and so much to give.
"But to thrive and succeed in life, these children need to get the right support.
"It's really important that Devon County Council works with parents and families to improve the quality of education, health and care plans for children who need them.
"This is vital for ensuring that deaf children are getting the help they need.
"I look forward to working with many of the really dedicated professionals at County Hall to improve the situation and make sure every deaf child in Devon can achieve their potential."
Jo Olsson, who chairs the Devon Children and Families Partnership Executive, said: "We fully accept all the findings and recommendations of the inspection.
"The inspection told us that our strategy and action plans are sound and the response to younger children with more complex needs works well.
"The commitment, dedication and hard work of leaders and staff is recognised and the educational outcomes for children with SEND are good in Devon."
Ms Olsson said improvements had been made in the production of individual Education, Health and Care Plans or EHCPs but there was still a long way to go.
"The SEND reforms were introduced in 2014 but our work as a partnership didn’t start in earnest until late in 2016,” she said.
"As a consequence, very many families experienced a service that was poor, which is unacceptable.
"We apologise sincerely and are all determined to build on our recent improvements.
"We know that families of children with SEND need the system to work well together and with them if the complex needs of their children are to be met, their children are to flourish in childhood and be ready to embrace all the challenges and opportunities that life has to offer.
"There are about 4,700 children with an EHCP in Devon. Too many found the partnership with professionals very difficult; they felt frustrated, anxious, angry, disappointed, distressed and upset.
"Some know that the system is getting better. They know that because they have experienced it, but many others don’t believe it. Trust and confidence are too low and must be rebuilt.
"Our delivery plan is delivering the improvements we need to see in the timeliness and quality of EHCPs, though we know there is still a long way to go.
"This means making a radical change in our relationships with each other and with parents.
"It is about more than communication, though this is vitally important, it is also about fundamental values of integrity, respect and courage.
"The inspectors recognised the joint commissioning strengths in the recent re-procurement of children’s community health services.
"Nevertheless, we know that we lost precious time, particularly in relation to the development of our response to autism spectrum disorder, an area where we also need to see radical change."
Click play to hear Jo Olsson, who chairs the Devon Children and Families Partnership Executive, speaking to reporter Tom Owen