A survey by Diabetes UK of 409 parents and carers of children with the condition found that 29 per cent were "less than satisfied" with school care and support.
The survey also found that more than a third of parents and carers (34 per cent) said their child does not have an individual healthcare plan that fully meets their needs in school.
And 14 per cent said their child had been excluded from extra curricular school activities such as physical education lessons and residential trips, due to their condition.
The findings come despite a change in the law in England last year, which gives all schools in the country a legal duty to ensure children and young people with medical conditions such as Type 1 diabetes, asthma and epilepsy get the care they need in school.
Barbara Young, chief executive of Diabetes UK, said: “We know that many schools are already providing good care to children and young people with Type 1 diabetes, and since the introduction of a new law in England to improve support in school for students with medical conditions, there has been huge improvements to the way diabetes support is delivered in schools.
“But every single child with diabetes who fails to get the care they need is being held back at a time when they are already facing the huge challenge of coming to terms with a serious lifelong medical condition, which can greatly affect their health and wellbeing, so it is essential that all schools get this right.”
In the UK around 35,000 children and young people under the age of 19 have diabetes with Type 1 diabetes being the most common – affecting around 96 per cent of sufferers.
Diabetes is complex condition that can pose many problems and can make school life more difficult.
Those with the condition have to be careful about what they eat, monitor their blood sugar levels, and will probably require insulin injections.
“Until we see all schools providing the care needed, they will continue to deny children and young people with Type 1 diabetes both the healthcare and the opportunity to thrive at school that they deserve,” Young added.
The charity has designed resources for schools and parents as part of the Type 1 diabetes: Make the Grade campaign, which contains information and guidance on how to provide effective care to all children and young people with diabetes.
