Next-generation sequencing (NGS) technologies and applications have enabled numerous critical advances in legume biology, from marker discovery to whole-genome sequencing, and will provide many new avenues for legume research in the future. The past 6 years in particular have seen revolutionary advances in legume science because of the use of high-throughput sequencing, including the development of numerous types of markers and data useful for evolutionary studies above and below the species level that have enabled resolution of relationships that were previously unattainable. Such resolution, in turn, affords opportunities for hypothesis testing and inference to improve our understanding of legume biodiversity and the patterns and processes that have created one of the most diverse plant families on earth. In addition, the genomics era has seen significant advances in our understanding of the ecology of legumes, including their role as nitrogen fixers in global ecosystems. The accumulation of genetic and genomic data in the form of sequenced genomes and gene-expression profiles made possible through NGS platforms has also vastly affected plant-breeding and conservation efforts. Here, we summarise the knowledge gains enabled by NGS methods in legume biology from the perspectives of evolution, ecology, and development of genetic and genomic resources.