Acacia melanoxylon, commonly known as the Australian blackwood, is an Acacia species native to south-eastern Australia. The species is also known as blackwood, hickory, mudgerabah, Tasmanian blackwood, or blackwood acacia. The tree belongs to the Plurinerves section of Acacia and is one of the most wide-ranging tree species in eastern Australia and is quite variable mostly in the size and shape of the phyllodes.

A. melanoxylon is able to grow to a height of around 20 m (66 ft) and has a bole that is approximately 150 cm (59 in) in diameter. It has deeply fissured, dark-grey to black coloured bark that appears quite scaly on older trees. It has angular and ribbed branches. The bark on older trunks is dark greyish-black in colour, deeply fissured and somewhat scaly. Younger branches are glabrous, ribbed and angular to flattened near the greenish coloured tips. The stems of younger plants are occasionally hairy. Like most species of Acacia, it has phyllodes rather than true leaves. The glabrous, glossy, leathery, dark green to greyish-green phyllodes have a length of 4 to 16 cm (1.6 to 6.3 in) and a width of 6 to 30 mm (0.24 to 1.18 in) with a variable shape. They most often have a narrowly elliptic to lanceolate shape and are straight to slightly curved and often taper near the base and have three to five prominent longitudinal veins.

In its native habitat it blooms between July and December producing inflorescences that appear in groups of two to eight on an axillary raceme. The spherical flower heads have a diameter of 5 to 10 mm (0.20 to 0.39 in) and contain 30 to 50 densely packed pale yellow to nearly white flowers. Following flowering smooth, firmly papery and glabrous seed pods form. The curved, twisted or coiled pods have a biconvex shape with a length of 4 to 12 cm (1.6 to 4.7 in) and a width of 5 to 8 mm (0.20 to 0.31 in) and contain longitudinally arranged seeds.

The species was first formally described by the botanist Robert Brown in 1813 as a part of the William Aiton work Hortus Kewensis. It was reclassified as Racosperma melanoxylon by Leslie Pedley in 1986 then returned to genus Acacia in 2006. Several other synonyms are known including Acacia arcuata, Mimosa melanoxylon and Acacia melanoxylon var. obtusifolia.

In its native range A. melanoxylon is found down the east coast of Australia from Queensland in the north, into New South Wales, through Victoria and west along the south coast of South Australia. It is also found along the east coast of Tasmania. It has become naturalised in Western Australia. In New South Wales it is widespread from coastal areas and into the Great Dividing Range but is not found further inland. It is commonly found at higher altitudes in the Nandewar Range, Liverpool Range and around Orange in the west. It is mostly found as a part of wet sclerophyll forest communities or near cooler rainforest communities. The range of the tree extends from the Atherton Tableland in northern Queensland and follows the coast to around the Mount Lofty Range in South Australia and can grow in a wide range of podsols, especially in sandy loams.

A. melanoxylon is valued for its decorative timber which may be used in cabinets, musical instruments and in boatbuilding.

Sapwood may range in colour from straw to grey-white with clear demarcation from the heartwood. The heartwood is golden to dark brown with chocolate growth rings. The timber is generally straight grained but may be wavy or interlocked. Quartersawn surfaces may produce an attractive fiddleback figure. The wood is lustrous and possesses a fine to medium texture.

The name of the wood may refer to dark stains on the hands of woodworkers, caused by the high levels of tannin in the timber.