Eucalyptus cajuputea, commonly known as the narrow-leaved peppermint box, is a mallee that is native to South Australia. The multi-stemmed tree of mallee grows to a height of 10 metres (33 ft) and has rough, hard to flaky, grey-brown bark up as far as medium branches and then smooth, coppery to pale grey to cream bark above. Adult leaves are dull to glossy, slightly blue-green to green with a blade that is approximately 13 centimetres (5.1 in) in length and to 130 mm long and 14 millimetres (0.55 in) wide and has a linear to narrow-lanceolate shape.