Abstract: The adoption of agriculture was perhaps the most momentous transformation in human history. It set into motion forces that changed our species from being a relatively minor player into one that dominated local ecosystems and is now changing the biophysical characteristics of the entire planet. We argue that this transformation can be understood as a leap to ultrasociality. After agriculture was adopted, numerous types of human societies competed with each other for local resources. Over millennia group selection favored those societies characterized by extensive division of labor, intensive and extensive resource exploitation, territorial expansion, and a type of social organization favoring the flourishing of the group itself over the well-being of individuals within the group. This type of social organization is rare in nature but wildly successful when it occurs. The social insects — ants, bees, termites, and wasps — made a similar leap in social organization and the broad characteristics of their societies are remarkably similar to human societies. We argue that this is a case of parallel evolution and that similar evolutionary forces are at work. Ultrasocaility can help explain the dramatic changes in the human condition after agriculture — the population explosion, the contradiction between declining individual well-being and the evolutionary success of our species, the human domination of local ecosystems, and our relentless exploitation of local resources. Viewing human societies as ultrasocial can offer insights not only about the transition to agriculture and its consequences, but also about the forces shaping the modern global socio-economic system.