Otago ( (listen), ; Māori: Ōtākou [ɔːˈtaːkou]) is a region of New Zealand located in the southern half of the South Island administered by the Otago Regional Council. It has an area of approximately 32,000 square kilometres (12,000 sq mi), making it the country's second largest local government region. Its population was 246,000 in June 2022.

The name "Otago" is the local southern Māori dialect pronunciation of "Ōtākou", the name of the Māori village near the entrance to Otago Harbour. The exact meaning of the term is disputed, with common translations being "isolated village" and "place of red earth", the latter referring to the reddish-ochre clay which is common in the area around Dunedin. "Otago" is also the old name of the European settlement on the harbour, established by the Weller Brothers in 1831, which lies close to Otakou. The upper harbour later became the focus of the Otago Association, an offshoot of the Free Church of Scotland, notable for its adoption of the principle that ordinary people, not the landowner, should choose the ministers.

Major centres include Dunedin (the principal city), Oamaru (made famous by Janet Frame), Balclutha, Alexandra, and the major tourist centres Queenstown and Wānaka. Kaitangata in South Otago is a prominent source of coal. The Waitaki and Clutha rivers provide much of the country's hydroelectric power. Vineyards and wineries have been developed in the Central Otago wine region. Some parts of the area originally covered by Otago Province are now administered by either Canterbury Regional Council or Southland Regional Council.