Poverty is a powerful stressor that influences growth and development in children, and physical and mental health throughout adulthood. Science and imaging technology are making its impact visible, demonstrating how the socioeconomic disparities that flow from historical injustice alter brain structures. We’re also learning that social capital can be a protective layer against the health effects of poverty, even as the gap widens between those who can access it and those who cannot. What does neuroscience tell us about poverty’s impact? How can we better use social capital and other tools to prevent or reverse the effects?