Ofsted praised the “inspirational and dynamic” leadership at The Evolution Centre in Bicton.
The school, which has 17 pupils aged 11 to 18, charges between £36,140 to £46,180 per year.
Inspectors, who visited the school between March 26 and 28, said there is a “broad and balanced” curriculum and teachers are “outstanding.”
Melanie Callaghan-Lewis, lead inspector, said the school can improve further by continuing to build upon the “strong personal development and behaviour” of pupils by making sure that pupils who miss enrichment activities due to absence have the chance to participate in this learning.
She said it should also sustain the positive engagement with parents, carers and external agencies to promote good attendance.
She said: “Leadership is inspirational and dynamic. The school is responsive to pupils’ needs.
“The flexible approach to teaching interests and motivates pupils. Pupils progress well from their starting points. Teaching and learning are outstanding. Pupils arrive with significant gaps in learning.
“Through careful planning and targeted support, they are able to catch up. Pupils who left last year achieved a wide range of qualifications.
“Staff are highly vigilant about safeguarding. Nothing is left to chance when it comes to the welfare and safety of pupils. Pupils say they feel safe at school.”
“Every aspect of the school’s work is focused on pupils’ needs and aspirations.
“Pupils develop social skills, learn about healthy relationships and benefit from high-quality careers education.
“They are well prepared for the next phase of their education or employment and training.”
She added: “Behaviour is exemplary. Pupils are proud of their achievements and proud of their school.
“Attendance for a small number of pupils is still low. However, there is a significant improvement on their attendance at previous settings.
“The school’s work is effective in reigniting a love for learning.”
A statement from the school said: “We celebrated our second 'outstanding’ Ofsted when the report was published on Friday.
“The amazing report recognised that ‘pastoral support is exceptional’ and that ‘the school goes above and beyond to provide experiences where pupils come out of their comfort zones and develop self-confidence and resilience’.
“The inspector also acknowledged the brilliant work being done by teachers to support students to progress from often low starting points.
“Well done to all, a brilliant result.”