Eucalyptus johnstonii, commonly known as Tasmanian yellow gum,[2] is a species of medium-sized to tall tree endemic to Tasmania.

It has smooth yellow to greenish bark, lance-shaped adult leaves, flower buds in groups of three, white flowers and hemispherical or bell-shaped fruit.Eucalyptus johnstonii is a tree that typically grows to a height of 40–50 m (130–160 ft) and forms a lignotuber.

Young plants and coppice regrowth have stems that are more or less square in cross-section with a broad wing on each corner and sessile.

Moore gave it the name Eucalyptus muelleri, a name that was already used for a different species, making it an illegitimate name.

[6][7][8] Tasmanian yellow gum grows in tall forest on mountains and plateaus in south-eastern Tasmania including on Mount Wellington, Bruny Island and the Tasman Peninsula.