Marmadua is a locality in the Western Downs Region, Queensland, located between Dalby and Moonie.
The locality name was the name of a pastoral station in the 1880s. By 1914, Marmadua Station was 205.5 square miles in size, and was carrying approx. 3500 cattle. In 1936, an artesian bore was sunk to a depth of 170 feet to provide water for the cattle.
The east, south and part of the west of the locality are within the Kumbarilla State Forest, which extends into a number of neighbouring localities.
In the 2021 census, Marmadua had a population of 15 people.