Middle School (Years 5-8) at Haileybury introduces parallel education where students are separated into single-gender classrooms for their academic studies and for sport and camping programs.

Although learning in separate classes, boys and girls share the same campus and socialise in co-curricular activities together.

[5] Haileybury maintains strong relationships with schools in Bangladesh, China, Japan, France, Sri Lanka, England, Indonesia and Timor-Leste.

[6] Haileybury is associated with the following schools: Charles Rendall, an old boy of Haileybury College,[8] Hertfordshire (1873) and graduate of Oxford University (1879), moved to Australia in 1882, becoming a teacher of Latin and Ancient Greek at Melbourne University, Melbourne Grammar, and later at Scotch College.

[10] In 1932 the third Headmaster, Sydney Dickinson, purchased what was then known as the 'Castlefield' Estate, in Hampton, Victoria, and from 1932 to 1939, Haileybury used both properties.

[17] He introduced to Haileybury the model of Parallel Education, a specialised Pre-Senior (Year 9) Program, a broadening of the curriculum, and the three-year VCE.

In 2019, it opened its first interstate campus, located close to Darwin, Australia, named Haileybury Rendall School.

[19] Rendall, an alumnus of Haileybury, England, obtained permission from his old school to use its name and badge.

[citation needed] In 1954, the school decided to couple the motto of Haileybury, England, 'Sursum Corda' ('Lift up your hearts') to the original 'Altera Terra'.

[citation needed] The Keysborough campus was established in the 1960s and consists of "Newlands" and the Senior School.

[citation needed] The Keysborough campus houses the David Bradshaw Chapel, a concert hall called "Aikman Hall", a newly refurbished library, a lecture theatre, an arts precinct, and several sporting ovals, hockey fields, and tennis courts, as well as an Olympic size swimming pool with diving facilities.

The campus has been labelled as Melbourne's first vertical school, with the building consisting of ten storeys with two terrace levels.