The King’s School in Gloucester has received the highest level of inspection report.
The school was inspected over three days in September by the Independent Schools' Inspectorate (ISI), the regulatory body for independent schools.
It included a regulatory compliance inspection and an inspection of educational quality across all areas of the school.
A team of six inspectors visited the school over three days and hundreds of questionnaires were completed by staff, pupils and parents to share their views too.
The inspection concluded that the quality of King's pupils' academic and other achievements is excellent, and the quality of the pupils' personal development is excellent too – the highest level possible to achieve.
The report commented: "Pupils are enthusiastic and purposeful, and their positive behaviour is supportive of learning and a harmonious school environment."
It also said: "Pupils develop secure moral and social awareness, knowing right from wrong, and they strive to contribute to others' well-being."
Headmaster David Morton said: "We are all absolutely delighted with the 2022 ISI inspection report.
"This immaculate set of comments is a tribute to the hard work of all the staff, pupils, governors, and of course parents, in supporting the school's vision.
"We aim to provide the very best that an independent, balanced education can offer to our pupils, so it was very rewarding to learn that the inspectors saw evidence of that in every area of the school.
"King's is a friendly, purposeful community which develops young people of character who will make a difference in the world around them and I could not be more proud of what we offer and achieve."