Studies of genes and social behavior, aided by new genomic resources, are coming of age. Here, we show how some of the insights that have emerged from research on the evolution of development (evo-devo) also provide a useful framework for studying the evolution of social behavior at the molecular level. These insights include co-opting old genes for new functions, phenotypic modularity, genetic tool kits, the importance of gene regulation in evolutionary change, and the influences of some genes over multiple timescales. We next outline a few differences between development and behavior that pose challenges for an evo-devo approach to behavior. For the remainder of this chapter, we review several studies that illustrate the relevance of evo-devo insights to our understanding of the evolution of behaviors related to eusociality in the insect societies.