We describe an ecological approach to understanding the developing brain, with a focus on the effects of poverty-related adversity on brain function. We articulate how combining multilevel ecological models from developmental science and developmental psychopathology with human neuroscience can inform our approach to understanding the developmental neuroscience of risk and resilience. To illustrate this approach, we focus on associations between poverty and brain function, the roles parents and neighborhoods play in this context, and the potential impact of developmental timing. We also describe the major challenges and needed advances in these areas of research to better understand how and why poverty-related adversity may impact the developing brain, including the need for: a population neuroscience approach with greater attention to sampling and representation, genetically informed and causal designs, advances in assessing context and brain function, caution in interpretation of effects, and a focus on resilience. Work in this area has major implications for policy and prevention, which are discussed. Public Significance Statement Millions of youth grow up in poverty and are exposed to an unequal share of adversity which impacts brain and behavior development. An ecological approach to developmental neuroscience can help to articulate the active ingredients associated with poverty that impact brain development. Better understanding how and why various adversities, including harsh parenting and neighborhood poverty, impact brain development can inform policies to prevent negative outcomes.