Approximately 40 reptile species once inhabited the sandstone gullies and ridges along the middle to lower reaches of Sydney Harbour. Terrestrial reptiles include representatives from the five lizard families found in Australia and the four terrestrial snake families. Aquatic reptiles include representatives from the one Australian freshwater turtle family. In the marine environment representatives of the two marine turtle families and the one marine snake family are occasional visitors to the harbour.

Some species of reptiles can still be found in gardens and parklands in the harbour-side suburbs. Other species now only persist in the harbour region in small reserves or the larger less intensively developed areas in the upper reaches of the northern tributaries. The two largest lizards, the Lace Monitor and Heath Monitor, and some of the larger snake species such as the Diamond Python, Death Adder and Tiger Snake probably no longer occur in the immediate vicinity of the harbour foreshores. The marine reptiles recorded from the harbour are 'occasional' visitors, that is they do not breed or appear to stay in the area for long periods.

All native reptile species are protected within New South Wales and enquiries regarding the collection or disturbance of these animals should be directed the New South Wales National Parks and Wildlife Service.