Acacia subtessarogona, commonly known as spreading gidgee, is a tree in the family Fabaceae. Endemic to Western Australia, it occurs only in a small area of the Gascoyne River catchment near Carnarvon. Spreading gidgee grows as an upright tree to seven metres high. Like most Acacia species, it has phyllodes rather than true leaves. These are flat, curved, and about eleven centimetres long. The flowers are yellow. The pods are between six and twelve centimetres in length, and have a distinctive groove along each edge.