Whadjuk, alternatively Witjari, are Noongar people of the Western Australian region of the Perth bioregion of the Swan Coastal Plain.

The Noongar are Aboriginal Australian people who live in the south-west corner of Western Australia, from Geraldton on the west coast to Esperance on the south coast. There are 14 different groups in the Noongar cultural bloc: Amangu, Ballardong, Yued, Kaneang, Koreng, Mineng, Njakinjaki, Njunga, Pibelmen, Pindjarup, Wadandi, Whadjuk, Wiilman and Wudjari. The Noongar people refer to their land as Noongar boodja.