The development of the hippocampus and amygdala is particularly sensitive to environmental factors, including socioeconomic status (SES). Studies that have investigated associations between SES and brain development markers have rarely focused on connectivity. Accordingly, this longitudinal study examined whether SES in infancy (parental education and income-to-needs ratio) predicts the functional connectivity of the hippocampus and amygdala in late childhood, and in turn whether functional connectivity is associated with child socioemotional adjustment in a middle-class sample. SES indices were measured when children (n = 28) were 7 months old. When children were 10 years of age, they underwent a resting-state functional magnetic resonance imaging exam, and their school teachers completed a questionnaire assessing child socioemotional adjustment. Whole-brain regression analyses, including left and right hippocampi and amygdalae as seeds and SES indices as predictors, revealed that higher parental education predicted stronger functional connectivity between the left and right hippocampi and the right amygdala with the dorsal anterior cingulate cortex, and between the left amygdala and bilateral angular gyrus, after accounting for child age and sex. In turn, the connectivity of these regions was associated with higher child prosocial behavior. These findings contribute to the emerging literature suggesting that SES is associated with variability in the neural substrates of social abilities in children.