This study was designed to determine whether a preventive intervention focused on enhancing supportive parenting could ameliorate the association between exposure to poverty and brain development in low socioeconomic status African American individuals from the rural South. To determine whether participation in an efficacious prevention program designed to enhance supportive parenting for rural African American children will ameliorate the association between living in poverty and reduced hippocampal and amygdalar volumes in adulthood. In the rural southeastern United States, African American parents and their 11-year-old children were assigned randomly to the Strong African American Families randomized prevention trial or to a control condition. Parents provided data used to calculate income-to-needs ratios when children were aged 11 to 13 years and 16 to 18 years. When the participants were aged 25 years, hippocampal and amygdalar volumes were measured using magnetic resonance imaging. Household poverty was measured by income-to-needs ratios. Young adults' whole hippocampal, dentate gyrus, and CA3 hippocampal subfields as well as amygdalar volumes were assessed using magnetic resonance imaging. Of the 667 participants in the Strong African American Families randomized prevention trial, 119 right-handed African American individuals aged 25 years living in rural areas were recruited. Years lived in poverty across ages 11 to 18 years forecasted diminished left dentate gyrus (simple slope, -14.20; standard error, 5.22; P = .008) and CA3 (simple slope, -6.42; standard error, 2.42; P = .009) hippocampal subfields and left amygdalar (simple slope, -34.62; standard error, 12.74; P = .008) volumes among young adults in the control condition (mean [SD] time, 2.04 [1.88] years) but not among those who participated in the Strong African American Families program (mean [SD] time, 2.61 [1.77] years). In this study, we described how participation in a randomized clinical trial designed to enhance supportive parenting ameliorated the association of years lived in poverty with left dentate gyrus and CA3 hippocampal subfields and left amygdalar volumes. These findings are consistent with a possible role for supportive parenting and suggest a strategy for narrowing social disparities.