Guided by family stress theory, relations among neighborhood stress, maternal psychological functioning, and parenting were examined among 123 low-income, urban-dwelling, African American single mothers. Using a longitudinal design, structural equation modeling was employed to test the hypothesis that neighborhood stress results in poorer parenting over time through its detrimental effect on maternal psychological functioning. Social support from family and friends was examined as a potential moderator of the association between neighborhood stress and parenting behavior. Results indicated that higher levels of neighborhood stress were related to greater psychological distress among mothers, which in turn, was significantly related to less engagement in positive parenting practices approximately 15 months later. A moderating effect emerged for social support, however, such that the proposed model provided a better fit for mothers reporting low levels of perceived social support than for mothers reporting high levels. Implications of the findings for prevention and intervention are discussed.