Waiuku is a country town in the Auckland Region in the North Island of New Zealand. It is located at the southern end of the Waiuku River, which is an estuarial arm of the Manukau Harbour. It is 40 kilometres southwest of Auckland city centre, and 12 kilometres north of the mouth of the Waikato River.
It was part of the Franklin District prior to it being abolished in 2010. Most of the town is now within the boundaries of Auckland Council, with the balance in the area of Waikato District Council.