Eucalyptus newbeyi is a mallee that typically grows to a height of 5–8 m (16–26 ft) and does not form a lignotuber.

[2][3][4] Eucalyptus newbeyi can be distinguished from the closely related Burdett gum (E. burdettiana) by its smooth, horn-shaped rather than warty operculum.

[5] Eucalyptus newbeyi was first formally described in 1980 by Denis and Stella Carr in the Australian Journal of Botany, from specimens collected by Alex George near the Fitzgerald River in 1970.

[3] The Beaufort Inlet mallee is found on steep slopes and on riverbank cliffs in shrubland near Beaufort Inlet and in the Fitzgerald River National Park, growing in sandy-clay-loam soils.

[2][3][4] This eucalypt is classified as "Priority Three" by the Western Australian Government Department of Parks and Wildlife,[2] meaning that it is poorly known and known from only a few locations but is not under imminent threat.