A revision of the Malagasy flea beetle genus Neodera Duvivier 1891 is provided. This genus includes 31 species of which 19 are new to science: Neodera amplicollis sp.n., N. breviantennata sp.n., N. didiensis sp.n., N. diversitarsis sp.n., N. jenisi sp.n., N. kraussi sp.n., N. longicollis sp.n., N. marojejyensis sp.n., N. nigrotibialis sp.n., N. opaca sp.n., N. pauliani sp.n., N. perroti sp.n., N. peyrierasi sp.n., N. reducta sp.n., N. similvadoni sp.n., N. sogai sp.n., N. speronata sp.n., N. straminoides sp.n. and N. vadoni sp.n.. The following two synonymies are proposed: N. fraterna Duvivier = N. amarella Bechyné and N. fulva Jacoby = N. hilari Bechyné. In addition, neotypes for N. emarginata Duvivier and N. fraterna Duvivier, and lectotypes for N. fulva Jacoby, N. imitatrix Duvivier, N. madagassa (Harold), N. picticornis (Harold), N. transversicollis Jacoby and N. varicornis (Harold) are designated. Additionally, the revision comprises a key for the identification of all 31 species considered, some habitus photos, microscope and scanning electron micrographs of many diagnostic characters, including median lobe of aedeagus and spermatheca. A first phylogenetic analysis based on parsimony is also provided. It is used with distributional data to put forward hypotheses about the natural history of the taxon in the light of the species differentiation models proposed thus far for Madagascar.