Waitemata Harbour is the main access by sea to Auckland, New Zealand. It connects the city and port to the Hauraki Gulf, and thus to the Pacific Ocean, and is sheltered from Pacific storms by the bulks of Rangitoto Island and Waiheke Island.

For this reason it is often referred to as Auckland Harbour, despite the fact that it is only one of two harbours surrounding the city.The Waitemata forms the north and east coasts of Auckland isthmus. It is matched on the south and west by the shallower waters of Manukau Harbour.

The harbour is an arm of the Hauraki Gulf, extending west for eighteen kilometres from the end of the Rangitoto Channel. Its entrance is between North head, in the suburb of Devonport, and Bastion Point in the south.

The westernmost ends of the harbour extend past Whenuapai in the northwest, and to Te Atatu in the west, as well as forming the estuarial arm known as the Whau River in the southwest.

The north shore of the harbour contains North Shore city, one of several separate cities within the Auckland metropolitan area. Suburbs located close to the shore here include Devonport, Northcote and Birkenhead.

To the south is the heart of Auckland city, as well as coastal suburbs such as Mission Bay, Parnell, Herne Bay, and Point Chevalier, the latter of which lies on a short triangular peninsula jutting into the harbour.

The harbour is crossed at its narrowest point by the Auckland Harbour Bridge. To the east of its southern end lie the marinas of Westhaven, Freemans Bay and the Viaduct Basin . Further east from these, and close to the harbour's entrance, lies the Port of Auckland.