The Great South Road is a major arterial road on the Auckland isthmus and South Auckland. Originally the northern section of the earliest highway between Auckland and Wellington, in the North Island of New Zealand, the road was the main route connecting Auckland to Hamilton. Many former sections of the road have been integrated into the Waikato Expressway. Currently four sections of the road remain: Epsom to Bombay in Auckland, the main street in Pōkeno, the former route of State Highway 1 that links the towns of Huntly, Taupiri, Ngāruawāhia and Horotiu, and the main road in Ōhaupō.

Many sections of Great South Road were constructed on ara hīkoi; traditional walking paths used by Tāmaki Māori.^[1] The first sections of Great South Road were constructed in 1843.^[2] In 1851, the Tāmaki Bridge was constructed between Ōtāhuhu and Papatoetoe, opening up the south for greater development.^[2] By 1855, the road had reached as far south as Drury, from which a track led towards the Waikato River.^[2] In 1861, Governor George Grey ordered the construction of the Great South Road further into the Waikato, to improve supply lines through swampy and thickly forested country, prior to the Invasion of the Waikato.^[3] The road was constructed by British Army troops, including Dominic Jacotin Gamble, and provided a flow of supplies for the Waikato campaign.^[4] Queen's Redoubt at Pōkeno was a major base of operations for soldiers working on constructing the road.^[5] Approximately 12,000 soldiers were involved in the construction over two years.^[6]

Toll booths were set up along the road in 1866 at Newmarket, Ōtāhuhu and Drury in order to pay for upkeep costs of the Great South Road.^[7] Travellers along the Great South Road complained about the excessive cost of these tolls, which were abolished in 1875.^[2] After the wars, more peaceful uses predominated, and the road became the main social and commercial link to the growing agricultural areas south of Auckland.^[6]

Much of the road between Newmarket and Drury was laid in concrete in the 1920s, up to one foot thick. The road was later covered with asphalt.^[6][8] Originally, the road was marked by milestones, but these are now all believed lost, although there is a ‘22 mile’ milestone marker outside Drury School, in Drury.^[6] The Auckland Southern Motorway has largely superseded Great South Road as a through route, but many parts of the road are still in use, particularly the urban sections.

The road begins in the central Auckland suburb of Epsom, then passes through the suburbs of Greenlane, Penrose, Ōtāhuhu, Papatoetoe, Manukau, Manurewa and Papakura. Leaving the urban sprawl, it heads south through Drury before terminating at Mill Road in Bombay and merging with the Waikato Expressway. Historically it continued, over the Bombay Hills, and followed the east bank of the Waikato River until crossing it at Ngāruawāhia. A section of State Highway 3 through Ōhaupō retains the road's southernmost extension.

Along the 42 km of road, there are many instances of duplicate addresses. The address numbering restarts six times, being differentiated in Google Maps by suburb. For example there are five "1 Great South Road" addresses.^[9]

• New Zealand state highway network