Great Mackerel Beach is a suburb about 43 kilometres north of the Sydney central business district, from 2016 in the local government area of Northern Beaches Council, Sydney, New South Wales, Australia, formerly part of Pittwater Council. It is on the western shores of Pittwater in Ku-ring-gai Chase National Park, beside Currawong Beach, and near Coasters Retreat and Palm Beach. The population was 36 at the 2016 census; the median age was 66, with an average of 0.3 children per family and an average of 2 people per household. The population was 301 at the 2011 census, and 103 in 2006.
Great Mackerel Beach is frequently referred to as Mackerel Beach or [Great] Mackeral Beach, although the spelling "Mackerel" is becoming standard.
Nearby Currawong Beach is sometimes called Little Mackerel Beach.