Walter George Woolnough was an Australian geologist.
Woolnough was born in Brushgrove, Grafton, New South Wales, and attended Sydney Boys High School, Newington College and the University of Sydney. In 1897, as an undergraduate, he accompanied Edgeworth David's expedition to Funafuti Atoll, where Charles Darwin's theory of the formation of coral reefs was tested.
Woolnough lectured in geology at the University of Sydney from 1898 and then at the University of Adelaide until 1912. He was the first Professor of Geology, University of Western Australia from 1913 to 1919 and geological advisor to the Commonwealth of Australia 1927-41.
Woolnough was awarded the Clarke Medal by the Royal Society of New South Wales in 1933.