<p id="C3">Foxtail millet (<italic>Setaria italica</italic>) was domesticated from the wild ancestor, green foxtail (<italic>S. viridis</italic>), about ten thousand years ago in China. Foxtail millet belongs to <italic>Setaria</italic> genus, which includes about 125 species of panicoid grasses worldwide, and 15 species of them in China varied from diploid to octoploid. Currently, six genomes in the <italic>Setaria</italic> genus have been identified by GISH (genomic in situ hybridization). Molecular phylogenetic analyses show that the <italic>Setaria</italic> genus is polyphyletic, in line with the characteristic of diversified genomes. Phylogeny of <italic>Setaria</italic> genus reveal that foxtail millet is most closely related with green foxtail, and then <italic>S. fabrei</italic> and <italic>S. verticillata</italic>, and that A genome of <italic>S. italica</italic>/<italic>S. viridis</italic> appears to be closer to B genome of <italic>S. adhaeran</italic> and C genome of <italic>S. grisebachii </italic>than the other known genomes. For utilization of wild species resources, foxtail millet breeders have successfully introduced the naturally mutated herbicide-resistant genes from green foxtail into cultivars, resulting in the herbicide-resistant foxtail millet variety. Here, we review the recent advances of wild species of foxtail millet in species classification, genome constitution and phylogenetic relationships, and highlight the utility of the wild species resources for breeding and domestication of foxtail millet. We also discuss the potentials of the wild <italic>Setaria</italic> species in discovery of domestication genes and breeding in foxtail millet in the future.