The figures come as the Association of School and College Leaders criticised the Ofsted system, warning schools deemed to be failing are destined to lose out on much-needed funds.
Department for Education data shows 11.24% of the 78,558 children in Cornwall attended schools rated 'outstanding' by Ofsted in 2021-22.
There were 1,947 pupils (2.48%) in Cornwall attending schools rated 'inadequate', Ofsted's lowest score.
When a school is judged to be inadequate it is placed in a 'category of concern', and will be required to become a sponsored academy, with another local school trust.
A further 73.16% of children attended good schools, while 12.59% were at schools deemed to require improvement.
There were 0.53% of children who attended schools that had not been rated by Ofsted. This may be because newly-opened schools, have not yet been inspected.
Ofsted inspectors visit every primary and secondary school about every four years for an inspection, and will give it one of four possible ratings – outstanding, good, requires improvement or inadequate.
Across England, 18% of pupils attended outstanding schools in the 2021-22 academic year, the most recent year data is available for.
Meanwhile, 69% were at good schools, 10% at ones that require improvement, and 2% at inadequate schools. 1% of children attended schools that had not yet been rated by Ofsted.
Some schools may have been inspected by Ofsted or re-evaluated since this data was collected.
Geoff Barton, general secretary of the Association of School and College Leaders, said the current Ofsted system led to the "ridiculous" situation where property prices are affected by a school's result, making it harder for poorer families to live near the best schools.
Mr Barton said: “We all want great schools for our children. The question is how we achieve that objective and the problem with the current system is that Ofsted ratings are simply counter-productive.
"Once you are deemed ‘requires improvement’ or ‘inadequate’ it’s the devil’s own job to escape that category because it’s harder to recruit staff and your pupil roll – and hence funding – falls."
"The system has to change so that inspection outcomes are more nuanced, supportive and genuinely aid improvement where it is needed," he added.
A Department for Education spokesperson said the Government has invested £14 billion to help local authorities create 1.2 million new school places since 2010.
They said: “Parents rightly want to know how their child’s school is doing and I fully support our approach to providing a clear one-word rating to inform their decisions.
"Ofsted has been central to our success in driving up school standards, with 88% of our schools now rated good or outstanding - up from 68% when this Government came into office.”