The Tasmanian blue gum, southern blue gum or blue gum (Eucalyptus globulus) is an evergreen tree, one of the most widely cultivated trees native to Australia. They typically grow from 30–55 m (98–180 ft) tall. The tallest currently known specimen in Tasmania is 90.7 m (298 ft) tall. There are historical claims of even taller trees, the tallest being 101 m (331 ft). The natural distribution of the species includes Tasmania and southern Victoria (particularly the Otway Rangesand southern Gippsland). There are also isolated occurrences on King Island and Flinders Island in Bass Strait and on the summit of the You Yangs near Geelong. There are naturalised non-native occurrences in Spain and Portugal, Akamas, and other parts of southern Europe, southern Africa, New Zealand, western United States (California), Hawaii and Macaronesia, Caucasus (Western Georgia).
The d'Entrecasteaux expedition made immediate use of the species when they discovered it, the timber was used to improve their oared boats. The Tasmanian Blue Gum was proclaimed as the floral emblem of Tasmania on 27 November 1962. The species name is from the Latin globulus, a little button, referring to the shape of the operculum.