Eucalyptus sideroxylon is a tree that typically grows to a height of 25–35 m (82–115 ft) and forms a lignotuber.

[3][5][6][7][8] Allan Cunningham recorded the name Eucalyptus sideroxylon in Thomas Mitchell's 1848 Journal of an Expedition into the Interior of Tropical Australia but did not provide a description of the plant.

The first formal description of the species was published in 1887 by William Woolls in Proceedings of the Linnean Society of New South Wales.

[11] Two subspecies of E. sideroxylon are accepted by the Australian Plant Census as at December 2019: Mugga ironbark is widespread and often abundant in woodland from south-eastern Queensland through New South Wales to Victoria.

High levels of polyphenols (stilbenoids and ellagitannins) in E. sideroxylon wood can explain its natural preservation against rot.