Glenunga International High School (GIHS), formerly Glenunga High School (GHS), is a publicly-funded international school in Adelaide, South Australia. It is located approximately 4 km (2.5 mi) south-east of the Adelaide city centre in the suburb of Glenunga, between L'Estrange and Conyngham Streets, adjoining the major thoroughfare Glen Osmond Road. The school serves the surrounding suburbs of the cities of Unley, Burnside and the Adelaide Hills.

Glenunga offers the Ignite program for gifted students as well as the IB Diploma Programme. As of  2024^[update] the principal is Wendy Johnson.^[4]

The school was established in 1903 from the defunct Adelaide Agricultural School (founded 1897 with Andrew Ferguson as headmaster) as the Preparatory School for the South Australian School of Mines and Industries. It was renamed the Junior Technical School in 1914 and then Adelaide Technical High School in 1918.^[1] The school and the Old Scholars Association marked 1998 as the centenary year.^{[citation needed]}

It was located at the School of Mines building (which houses Brookman Hall — named for benefactor George Brookman) on the corner of North Terrace and Frome Road, now part of the City East campus of the University of South Australia. The school population outgrew the campus, so in 1964 it was relocated to its current location in Glenunga, and was renamed Glenunga High School in 1974. It adopted its current name upon the introduction of the International Baccalaureate Diploma Programme in 1990–91 with the aid of The Honourable Greg Crafter,^[5] a development which was instigated to help save the school from closure due to dwindling student numbers. With enrolments rising, GIHS has subsequently attracted substantial government funding and construction projects, most notably the technology and science wing extensions, a new administration block, and a performing arts centre; since 2005 there have been various additional changes to the facilities, such as extra rooms.

In 2013, development began for a new $10 million building to accommodate the growing number of students.^[6] This new building was accompanied by the renovation of the Music, Sciences and Art departments, as well as a new library. The development upgrades were completed in 2014.^[7]

In 2020, the construction for new buildings including technology facilities, science labs and classrooms began. The total cost of the new plan is roughly $32 million.^[8] The construction has been completed at the start of 2022 for the introduction of year 7s into the school, which fully opened to students and staff in mid-Term 1.

Glenunga International High School hosts an array of extracurricular groups, all of which are student-run. These include special-interest clubs, a variety of community service organisations, as well as various sporting teams.^[9] As of 2015, Glenunga has over 50 student-led clubs, which include Literature, Musical Theatre, Debating, Chess, Science and Raspberry Pi, amongst others.

Glenunga International High School has an extensive student leadership model, which gives any student the opportunity to make change within the school community. This includes the Learner, International Mindedness, and Wellbeing Councils, student driven bodies who co-ordinate events and a number of other responsibilities.

Glenunga continues to foster some of the academically highest-achieving students in the state.^[10]

In 2016, 20 students across both the SACE and IB diplomas achieved an ATAR of 99 or more — a score in the top 1% of students nationwide for that year.^[11]

• Daniel Becker – Sciences teacher,^[12] 2019, current^{[clarification needed]}
• Dave Dallwitz – Art teacher, c. 1954–1964^[13]
• Ivor Francis – Art teacher, 1944–1947^[13]
• Doru Frîncu (Francu) – P. E. teacher, 2009–present^[14]
• Sam Kellett – English teacher, 2013–2014^[15]
• Geoff Kemp – English and Drama teacher, current^[16]
• Paul Mildren – Member of the Australian baseball team;^[17][18] P. E. teacher, 2015–present^[19]
• Joe Scalzi – Social sciences, 2008–2010^[20]
• Rex Wright – P. E. teacher, 2011–2020^[21]