Middlemarch is a small town in the Otago region of New Zealand's South Island. It lies at the foot of the Rock and Pillar Range of hills in the broad Strath-Taieri valley, through which flows the middle reaches of the Taieri River. Since local government reorganisation in the late 1980s, Middlemarch and much of the Strath-Taieri has been administered as part of Dunedin city, the centre of which lies some 80 km to the southeast. Middlemarch is part of the Taieri electorate (formerly known as Dunedin South), and is currently represented in parliament by Ingrid Leary. Middlemarch has reticulated sewerage but no reticulated water supply. A description of 1903, that "[T]he summer seasons are warm, but not enervating, and the winters cold, but dry" is still true today.

It is a crucial service town for the local farming community, the terminus of the Taieri Gorge Railway, and the start of the Otago Central Rail Trail.

Several suggestions exist about how the township was named. One is that Mrs Alice Humphreys (née Hawdon, 1848–1934), whose husband Edward Wingfield Humphreys owned and had surveyed for sale sections in this new township, named the town in 1876 after George Eliot's novel Middlemarch: A Study of Provincial Life. Another is that the name is from the now obsolete English term "march" meaning a boundary - in this case a middle area between two rivers. As with many places in and close to the Maniototo area, its name may have been influenced by the Northumberland ancestry of early surveyor John Turnbull Thomson (there is a Middle March region in Northumberland, centred on the town of Otterburn).