Rail transport in New Zealand is an integral part of New Zealand's transport network, with a nationwide network of 4,375.5 km (2,718.8 mi) of track linking most major cities in the North and South Islands, connected by inter-island rail and road ferries. Rail transport in New Zealand has a particular focus on bulk freight exports and imports, with 19 million net tonnes moved by rail annually, accounting for more than half of rail revenue.

Railways with a track gauge of 3 ft 6 in were first constructed as horse-drawn wagonways. The first intercity passenger railway to use 3 ft 6 in was constructed in Norway by Carl Abraham Pihl. From the mid-nineteenth century, the 3 ft 6 in gauge became widespread in the British Empire. In Africa it became known as the Cape gauge as it was adopted as the standard gauge for the Cape Government Railways in 1873, although it had already been established in Australia and New Zealand before that. It was adopted as a standard in New Zealand, South Africa, Indonesia, Japan, the Philippines, Taiwan, and Queensland in Australia.