About Us


St Andrew’s celebrated 20 years of being a coeducational school in 2019.


We believe that coeducation is normative for life and prepares students for the world in which they will live, study and work after they leave school. A coeducational learning environment also reinforces our values of equal opportunity, diversity, harmony and inclusiveness.

Our learning environment

We seek to provide a learning environment that is engaging and academically enriching for both girls and boys, from Kindergarten through to Year 12. By focusing on delivering quality teaching and student wellbeing programs, we believe all students can thrive academically, socially and emotionally, being encouraged and supported to develop their God-given abilities.

Head of St Andrew’s Cathedral School Dr John Collier believes that a coeducational learning environment provides the best foundation for the social and emotional development of students.

“In my 44 years of teaching, I have found that each gender seems to complement the other; the energy and vitality of the boys, who are so full of beans, seems to rub off on the relational nature of girls – and vice versa,” he said. “A coeducational environment curbs the excesses of each gender in a positive way, making for more well-rounded people, who can relate to a diverse range of people. Moreover, boys and girls who do not conform to gender stereotypes, also thrive at SACS.”

Dr John Collier, Head of School

Social and Personal Development

We deliver student wellbeing programs that encourage healthy friendships between genders. We promote equal opportunity for men and women on our staff and seek to model respect for the opposite sex both inside and outside the classroom. We believe this kind of learning environment enhances the quality of relationships our students have with teachers and other students and will enable them to easily transition to the tertiary and work environment that students face after Year 12.

History of SACS and its decision to become coeducational

From its beginnings in 1885 up until 1999, St Andrew’s Cathedral School was a school for boys. The decision to admit girls was a long time coming, with discussions first arising in the 1970s. In 1999, the headmaster overseeing the introduction of girls, initially to the Senior College, Mr Phillip Heath, said the school needed to find its own place among Sydney’s independent schools. By including girls, St Andrew’s would become distinctive among many other long-standing independent schools in Sydney’s inner suburbs that remained boys- or girls-only schools. In short, we could offer what many of our competitors could not.

Our city location also marked us as unique and it was believed the opportunities provided by a pre-university style of campus for Year 10-12 students would be enhanced with the addition of girls. It also meant whole families could be accommodated at the school. Becoming coeducational was seen as a better cultural fit for our location, where we desire to build connections with local institutions, local businesses and government authorities where both genders are represented.

In 2008, the school became fully coeducational, with girls invited to enrol from Kindergarten right through to Year 9, making it the only coeducational Kindergarten to Year 12 school in the city centre.

What the research says about coeducational learning environments

For a long time, it was thought that single sex classroom environments produced better academic outcomes (particularly for girls) than coeducational environments. However, the research to prove this case has since been found to be inconclusive as it relied on the perceptions of students, teachers and parents who had pre-conceived views in this area.

Research that has promoted the benefits of single-sex schooling has also often neglected the significant impact of socio-economic factors, differences in school ethos, racial/cultural factors and individual differences. Studies that controlled these factors found a statistically insignificant difference between the academic achievements of students in single sex vs coeducational learning environments. (1)

A 2014 meta analysis looking at 184 studies comprising 1.6 million students in 21 countries found that “there is little evidence of an advantage of single sex schooling for girls or boys for any of the outcomes”. In fact, the major difference is in educational aspirations, which appear to be higher in co-ed schools.

When renowned educational researcher Professor John Hattie examined the effect of gender separation on student outcomes in his well-known meta-analysis of influences on learning (examining 500,000 studies of the effects of influences on student achievement), there was little to suggest that gender-based segregation offered any academic advantage. Hattie ranked single sex schooling as 179th (out of 195) as an influence on student achievement, with an effect size of 0.08, regarded as ‘trivial’.

Hattie stated, “I therefore suggest that we should focus on the greatest source of variance that can make the difference – the teacher. We need to ensure that this greatest influence is optimised to have powerful and sensationally positive effects on the learner.”

Well-known Australian researcher and expert on gender issues in education, Dr Judith Gill, wrote that “once the factors of ability and socio-economic background are taken into account, there is no empirical evidence to support the belief that in single-sex schools, girls do better than their counterparts in coeducational schools in terms of personal confidence or academic success, including the key subjects of maths, science and technology.” (2)

In 2015, she added: “Schools with excellent teachers, a concerned and involved parent community, inspired leadership and a good spread of relevant resources are to be found in both single sex and coeducational institutions. These features are much more important than the issue of gender context.” (3)

The Australian independent school landscape

Of the 720 independent secondary schools operating in Australia in 2016, 616 were coeducational. In the last 50 years, less than 2 per cent of more than 500 new independent secondary schools established in Australia have been single sex schools. In Australia, 48 coeducational schools have been created from what were originally single sex schools. So, there is clear growth in the number of coeducational schools in Australia and a significant decline in single-sex institutions.


At St Andrew’s, we firmly believe that coeducation normalises friendships between genders, and this diversity of friendships improves student wellbeing, a factor that is essential for academic success. We believe a coeducational setting, combined with outstanding teaching and student wellbeing programs, provides the ideal environment for all of our students to thrive academically, socially and emotionally.


(1) Guest, Murray (2014). The Single Sex v Coeducation Debate and the experience of Schools that Change Status. Download the Coeducation research paper here.
(2) Gill, Judith (2004). “Beyond the great divide: single sex schooling or coeducation?”
(3) Gill, Judith (2015). “Changing from single sex to co-ed can be good if based on educational (not economic) reasons” in EduResearch Matters. Read More

Vision and Mission