大桉（学名：Eucalyptus grandis）为桃金娘科桉属下的一个种。

Eucalyptus grandis, commonly known as the flooded gum or rose gum, is a tall tree with smooth bark, rough at the base fibrous or flaky, grey to grey-brown. At maturity, it reaches 50 metres (160 feet) tall, though the largest specimens can exceed 80 metres (260 feet) tall. It is found on coastal areas and sub-coastal ranges from Newcastle in New South Wales northwards to west of Daintree in Queensland, mainly on flat land and lower slopes, where it is the dominant tree of wet forests and on the margins of rainforests.