Black South African youth are disproportionately affected by the HIV epidemic, and risky sexual behaviors increase youths’ vulnerability to HIV infection. U.S.-based research has highlighted several contextual factors that impact sexual risk, but these processes have not been examined in a South African context. In a sample of Black South African parent-youth dyads, this study examined relations among parenting, neighborhood quality, maternal social support, coparenting, and youth sexual risk. Hypotheses were evaluated using structural equation modeling. Results revealed that better neighborhood quality predicted less youth sexual risk via higher levels of positive parenting. Social support was positively related to parenting quality but did not interact with neighborhood quality to impact parenting. Coparenting did not moderate the relation between parenting and sexual risk. Results highlight the importance of family- and community-level processes for youth sexual risk in an understudied and high-risk sample. HIV prevention-interventions should be informed by these contextual factors.