Acaciella is a Neotropical genus of flowering plants in the legume family, Fabaceae, and its subfamily Mimosoideae. Its centre of diversity is along the Mexican Pacific coast. They are unarmed, have no extrafloral nectaries and the polyads of their pollen are 8-celled. Though its numerous free stamens (sometimes >300) is typical of Acacia s.l., it has several characteristics in common with genus Piptadenia (tribe Mimoseae). Its pollen and free amino acids resemble that of Senegalia. Molecular studies place it sister to a monophyletic clade comprising elements of genus Acacia, and the tribe Ingeae. A nectary ring is present between the stamens and ovary, in common with Acacia subg. Aculeiferum.