A new genus of stingless bees (Apinae: Meliponini) is described and figured from Indonesia (Sulawesi), known from a single species previously placed in Geniotrigona Moure. Based on recent phylogenetic studies, Trigona (Geniotrigona) incisa Sakagami and Inoue renders Geniotrigona polyphyletic and is more closely related to Lepidotrigona Moure. The species is transferred to Wallacetrigona Engel and Rasmussen, new genus, and differentiated from Geniotrigona proper as well as all other meliponines occurring in Sundaland, Wallacea, and Sahul (Australinea). The new genus occurs east of the Wallace Line and separate from the distribution of Geniotrigona, which is otherwise restricted to Sundaland, but Wallacetrigona is presently not known beyond the Weber Line. A hierarchical classification of Indomalayan and Australasian stingless bees is tabulated and a revised key to the genera and subgenera provided, as well as an appendix tabulating the species and synonyms. The following new combinations are established: Wallacetrigona incisa (Sakagami and Inoue), Homotrigona (Lophotrigona) canifrons (Smith), Homotrigona (Odontotrigona) haematoptera (Cockerell), Homotrigona (Tetrigona) apicalis (Smith), H. (T.) binghami (Schwarz), H. (T.) melanoleuca (Cockerell), H. (T.) peninsularis (Cockerell), and H. (T.) vidua (Lepeletier de Saint Fargeau).