The eucalypti grow rapidly, and many species attain great height. Eucalyptus wood is extensively used as fuel, and the timber is commonly used in buildings and fencing. There are more than 700 species of eucalyptus and most are native to Australia. Species of eucalyptus are cultivated widely in the tropical and temperate world, including the Americas, Europe, Africa, the Mediterranean Basin, the Middle East, China, and the Indian subcontinent. However, the range over which many eucalypts can be planted in the temperate zone is constrained by their limited cold tolerance.

The Blue Mountains of southeastern Australia have been a centre of eucalypt diversification; their name is in reference to the blue haze prevalent in the area, believed derived from the volatile terpenoids emitted by these trees.