Jack Butler (4 May 1901 – 10 May 1986) was the last native speaker of the Jiwarli language of Australia.
As the last speaker, he was the primary source for the documentation of the language. He was the son of a white father, a shepherd named Dick Butler, and an aboriginal Australian mother, Silver. He was raised by his mother and his mother and stepfather, Jinapuka, also aboriginal, in Ulwarra Station and Glen Florrie Station, in Australia.
In Glen Florrie Station he lived in a camp with aboriginals. He learned their languages and customs from the elders. His favorite language was Jiwarli, which he learned from a man named Wangki, known to white Australians as "Stumpy." He also learned to speak Jurruru and Thalanyji. Most of his adult life was spent in Mount Stuart Station, where he came into contact with the Western lifestyle. He married Molly Ashburton in 1927 and had four children with her. He retired in Onslow in the 1970s and died in Carnarvon on 10 May 1986.