Acacia leiophylla, commonly known as coast golden wattle, is a tree of the family Mimosaceae native to South Australia and Western Australia.

The shrub or tree can grow to a maximum height of about 4 m (13 ft). It has flexuose and glabrous branchlets. Like most species of Acacia it has phyllodes rather than true leaves. The thinly coriaceous and glabrous evergreen phyllodes are sickle shaped with a length of 10 to 13 cm (3.9 to 5.1 in) and a width of 15 to 22 mm (0.59 to 0.87 in) and are narrow at the base with one main nerve per face and no lateral nerves.

It was described by botanist George Bentham in the London Journal of Botany in 1842. Similar in appearance to A. pycnantha, it can be distinguished by its lighter phyllodes.

It is situated along the south coast of South Australia where its range extends from around Coffin Bay on the Eyre Peninsula in the west to around Mount Gambier in the east where it is mostly found growing in sandy or loamy soils as a part of open scrub communities and is often associated with Mallee Eucalyptus species.