Independent co-ed combined school (R–12) in Belair, SA, with 1009 students.
NAPLAN modestly above national year-level averages and a median ATAR of 87.0; the result is a B overall.
St John's Grammar School is also known as SJGS and SJGS Belair.
Median ATAR 87.0 ranks #6 of 8 South Australia schools. Within South Australia Independent schools, ranks #3 of 5.
42.0% of students achieved ATAR ≥ 90 — #5 of 11 South Australia schools.
St John's Grammar School has an overall SchoolRank score of 58.3/100, rated "Average". This score is calculated from academic results, student growth, wellbeing, extracurricular programs, and value for money. Academically, the school scores 63/100, indicating moderate performance relative to other Australian schools. The school's ICSEA (Index of Community Socio-Educational Advantage) is 1141, well above the national average of 1,000.
In 2025 NAPLAN testing at St John's Grammar School, Year 3 students averaged 425 across the tested NAPLAN domains, above the national average of 407 for that year level, and Year 5 students averaged 505, above the national average of 490 for that year level, and Year 7 students averaged 553, above the national average of 540 for that year level, and Year 9 students averaged 605, above the national average of 569 for that year level. Relative to national year-level averages, the school's strongest domain is Writing. National averages are specific to each year level, because NAPLAN scores are scaled so older year levels score higher, a school-wide average can't be compared with a single national figure.
St John's Grammar School is a large independent combined school with approximately 1,009 students. It offers education for years R-12. As a independent school, enrolment typically involves an application process. Contact the school directly for enrolment criteria, waiting lists, and open day information.
St John's Grammar School has a student-to-teacher ratio of 12.3:1. This is below the national average of approximately 14:1, meaning students generally receive more individual attention. Support staff make up 33% of the workforce, providing additional learning assistance and pastoral care. The student attendance rate is 92%, which is strong.
St John's Grammar School has a median ATAR of 87.0. 42% of students achieved an ATAR above 90.
St John's Grammar School is located in Belair, SA, classified as a major cities school. With an ICSEA of 1141 (94th percentile), the school community's socio-educational advantage is above average, families tend to have higher education and income levels. ICSEA measures the educational advantage of a school's community, not the school's quality, a lower ICSEA school with strong academic scores may indicate particularly effective teaching.