The Hutt Valley is the large area of fairly flat land in the Hutt River valley in the Wellington Region of New Zealand. Like the river that flows through it, it takes its name from Sir William Hutt, a director of the New Zealand Company in early colonial New Zealand.

The river flows roughly along the course of an active geologic fault which continues to the south to become the main instrument responsible for the uplift of the South Island's Southern Alps. For this reason, the land rises abruptly to the west of the river. To the east, however, two floodplains have developed. The first of these is located between 22 and 15 kilometres from the mouth of the river. Beyond this, the river is briefly confined by a steep-sided gorge near Taita (aptly pronounced "tighter"), before the land opens up into a long triangular plain close to the river's outflow into Port Nicholson harbour.

The lower valley contains the City of Lower Hutt (also called Hutt City) while the adjacent, larger but less populous city of Upper Hutt has its business heart on the smaller plain above the Taita Gorge. The area forms a major dormitory suburban area for Wellington City as well as being a location for manufacturing and heavy industry and educational facilities.

Petone, at the Port Nicholson shoreline, was proposed as the initial site for the settlement of Wellington by the Wellington Company. However, as the chosen site was soon seen to be prone to river flooding, early settlement was relocated to the present Wellington City. A small settlement remained at the Petone site as the whole valley was believed to be well suited as farm land.

In 1846 there was fighting between Maori tribes and the Government, known as the Hutt Valley Campaign.

Almost the whole valley was subsequently clearfelled and converted to pasture or market gardens before the urbanisation of the 20th century. A small remnant of the early podocarp forest is preserved in Barton's Bush in Upper Hutt.