The Taieri Plains are an area of fertile agricultural land to the southwest of Dunedin, in Otago, New Zealand. The plains cover an area of some 300 square kilometres, with a maximum extent of 30 kilometres.

The floodplains of the Taieri and Waipori Rivers, the plains are enclosed to the west by the Maungatua and Silverpeaks Ranges, and to the south and east by a low range of coastal hills.

Dairy and sheep farming dominate the agriculture of the plains, although deer is starting to have an economic impact. The alluvial nature of the land means that floods are not uncommon, especially in the area around the confluence of the two rivers. Stopbanks protect State Highway 1 across parts of the plain, with the result that this stretch of road is known locally as The "floodfree" highway.

To the northeast, the city of Dunedin is separated from the Taieri Plains by a range of rugged hills which are part of the crater of an extinct volcano. At the northestern limit of the plain lies the town of Mosgiel, officially part of the city of Dunedin. Other settlements and towns on the plains include Outram, Henley, Allanton, and Momona, which is the site of Dunedin's international airport.

To the southwest, rolling hill country separates the Taieri Plains from South Otago's other main lowland areas around the Tokomairiro Plain and Clutha River. The twin lakes of Waihola and Waipori sit within these hills.