This article critically examines the psychological and policy implications of the belief that characteristics of social groups are grounded in biology and thus are unchangeable. We specifically focus on how this immutability mind-set may perpetuate group-based educational achievement gaps and deter treatment seeking for mental/behavioral health conditions. We then consider the prospect of plasticity: the notion that psychological attributes, although rooted in our biological endowment, are inherently malleable. Our discussion reviews the evidence for—and social implications of—this alternative mind-set for intellectual achievement as well as mental/behavioral health. We conclude by describing several concrete policy applications of a plasticity perspective.