All Hallows' School (AHS) is a Catholic day school for girls, located in Fortitude Valley, close to the central business district of Brisbane, Queensland, Australia. Founded in 1861, the school is a day school, having had a boarding school attached to it for many years. It follows in the tradition of the Irish Sisters of Mercy, and caters for more than 1,550 girls from Years five to twelve. The school was the first permanent home of the Sisters of Mercy in Queensland, and is the oldest surviving secondary school in Brisbane.