Dilworth School, often referred to simply as Dilworth, is an independent full boarding school for boys in Auckland, New Zealand. It is the largest full boarding school in both the country and Australasia. Owned and operated by a charitable trust, boys selected to attend do so on scholarships covering education and boarding costs.

Dilworth School was founded under the terms of the will of an Auckland farmer and businessman, Irish born James Dilworth who died in 1894.

He and his wife Isabella had no children of their own and left their wealth to establish a school with a goal of educating sons of people from the top two-thirds of the North Island who had suffered some family misfortune and were unable to afford the education they wanted their children to have.

The school opened in 1906 with eight boys and for the first 21 years offered primary education only. Secondary boys at that time boarded at the school but attended Auckland Grammar School during the day. The original school buildings were Dilworth's old farm homestead and outbuildings. Classrooms and other buildings were added later.

A secondary department was built in 1931. A major expansion started in 1956, the 50th anniversary, with the foundation stone being laid for St Patrick's Chapel. The total roll when that phase of the expansion was completed some five years later, was 300.

The next major jump in numbers was in 1993 when the present Junior Campus was built to accommodate 192 boys. This brought the total roll of both campuses to 510 covering Year 5 to Year 13.

In December 2019, Dilworth presented a vision to create a girls' boarding school to open in 2025.

Dilworth's boarding houses are named for places and counties in Ireland. The Junior Campus houses are Cotter and Gibson and Senior Campus houses are Tyrone, Dungannon, Donegal, Armagh, and Wilton with a recent addition of Donaghmore and Aghalee as new Year 9 houses.