Masterton is a large town in the Greater Wellington Region of New Zealand that operates as the seat of the Masterton District. It is the largest town in the Wairarapa, a region separated from Wellington by the Remutaka ranges. It stands on the Waipoua stream between the Ruamāhunga and Waingawa Rivers – 100 kilometres north-east of Wellington and 39.4 kilometres south of Eketāhuna.

Greater Wellington, also known as the Wellington Region, is a non-unitary region of New Zealand that occupies the southernmost part of the North Island. The region covers an area of 8,049 square kilometres (3,108 sq mi), and has a population of 550,500.