The Weilwan (also known as Wayilwan, Wailwan, Ngiyampaa Wailwan and Ngemba Wailwan) are an Aboriginal Australian people of the state of New South Wales. They are a clan of the Ngiyampaa nation.
The Weilwan ethnonym is derived from their word for "no" in the Ngiyambaa language, (weil/wail/wayil).
Like other Ngiyampaa people such as the Wangaaypuwan, they also referred to themselves according to their home country.
Main article: Ngiyambaa language
The Weilwan spoke the dialect of Ngiyambaa called "Ngiyampaa Wayilwan" and as such also called themselves "those who speak Ngiyampaa the Wayilwan way".
Weilwan country covered 5,000 square miles (13,000 km2), running along the southern bank of the Barwon River from Brewarrina to Walgett, and along Marra Creek and the Castlereagh, Marthaguy, and Macquarie rivers. Their southern frontier was at Quambone and in the vicinity of Coonamble.
The Weilwan were divided into kin groups, one of which is known: the Waiabara.