Eucalyptus microtheca, with many common names including desert box, coolibah, callaille, targoon, yathoo[2] or coolabah, is a species of tree that is endemic to northern Australia.

[2][3][4] Eucalyptus microtheca was first formally described in 1859 by Ferdinand von Mueller in the Journal of the Proceedings of the Linnean Society, Botany, from samples he had collected in 1855 along the Victoria River in the Northern Territory.

[3] Eucalyptus microtheca is most closely related to the widespread E. coolabah which is found in similar but drier habitats to the south and south-east.

[9] The wood produced by the tree is extremely hard and difficult to work with but is excellent for firewood and makes long-lasting fence posts that resist weathering and insects.

[10] Oils extracted from the leaves and blossom of the plant contain 101 compounds including α-pinene, O-cymen, β-pinene, aromadendrene, α-phellandrene and globulol.