常桉（学名：Eucalyptus crebra）为桃金娘科桉属下的一个种。

Eucalyptus crebra, commonly known as the narrow-leaved ironbark or narrowleaf red ironbark, is a type of Ironbark tree native to eastern Australia. A member of the large genus Eucalyptus, this tree is in the Myrtaceae family and can grow to a large spreading tree up to 35 m (100 ft) high. It is an important source of nectar in the honey industry and its hard, strong timber is used in construction.