Hamilton High School was opened to students on 10 July 1911, on the current site of Hamilton Girls' High School. The first Principal was Eben Wilson and he was followed by Mr H D Tait in 1937.
In 1955, Hamilton High school was divided into separate boys' and girls' schools, and Hamilton Girls' High School retained the original site with Joan Ellis being the first principal. She was followed by Lesley Anderson in 1958, Pat Edbrooke in 1969, Lyn Scott in 1982, Judith Miles in 1988, Lil Garland in 1998 and Mary Ann Baxter 2004. The current principal is Marie Gordon, who started in 2013.
The buildings have changed significantly over the years – all that remains of the original school is the front steps to the original building, and these now lead to the Wharenui and Wharekai and Maori Language area.[citation needed]
The school has a boarding hostel, Sonninghill, which caters for 130 girls.
The Hamilton High and Girls' High School Old Girls' Association supports Hamilton Girls' High School and has three functions a year which any past pupil can attend.[3]