The Mackellar Girls Campus of Northern Beaches Secondary College, formerly Manly Vale High School and Mackellar Girls' High School, is a government-funded single-sex secondary day school for girls located in Manly Vale, a suburb on the Northern Beaches of Sydney, New South Wales, Australia.

[citation needed] In 2015 it was ranked as the third top comprehensive girls' school in New South Wales.

[3][needs update] Mackellar has a house system to facilitate school based competitions and activities.

House activities include athletics, swimming carnivals and other sport related events.

The school currently has four houses created based on the Aboriginal meanings for Australian native birds:[4]