The Dilworth Building is an elegant office building at the seaward end of Queen Street in central Auckland. It was designed by the renowned local firm of Gummer and Ford, and was intended to be one of two similar structures on either side of the road, creating a gateway or 'Urbis Porta' (City Gate) to the commercial district. The building was erected as a high-quality, Portland stone and concrete structure by the Dilworth Trust in 1925-1927 to provide regular rental income for a school for disadvantaged boys. The school was originally known as the Dilworth Ulster Institute and had been founded at the bequest of James Dilworth (1815-1894), an early Irish settler, to educate boys from Auckland, and Ulster in Ireland.

The structure was built with a distinctive corner turret that made it one of the most prominent buildings in the city. The Dilworth Trust office and boardroom occupied the top and most prestigious floor of its nine storeys (including mezzanine), while the remainder was rented out to tenants. The building was partly occupied by the American consulate for many years, and used as US Army headquarters during the Second World War. Its use continues to include mixed offices and shops, and although sold by the Dilworth Trust in the 1980s it retains some original interiors.

A fine example of early twentieth-century commercial architecture, the Dilworth Building is extremely unusual in having been built by an educational trust. It is a reminder of the role played by philanthropy in the development of New Zealand education and of the colonial links between this country and Ireland. It commemorates a prominent early settler and member of the Provincial Council, and makes a significant contribution to the urban streetscape of central Auckland. It is one of a group of high-rise commercial buildings in the area that demonstrate Auckland's prosperity in the early twentieth century.