African American adolescents are at elevated risk for HIV and sexually transmitted infections. Risk reduction efforts have focused on parent-child communications, despite inconsistent findings regarding their association with adolescent sexual risk behaviors. The present study included sexually active African American adolescents and their parents/guardians (N = 125 dyads). All participants reported on frequency of sexual health conversations and adolescents reported recent occasions of protected and condomless sex. Analyses examined the congruence between parent-child communication reports and the association between this congruence and adolescent condomless sex. Parents and adolescents disagreed on the frequency of sexual health communication: 30% of parents reported such conversations as frequent, whereas only 2% of adolescents did. Parent-reported sex communication was negatively associated with adolescent condomless sex, while adolescent-reported communication was not. The moderation hypothesis was supported in that adolescent-reported sex communication was negatively associated with adolescent condomless sex only among parent-child dyads high in agreement on sexual health communication. Promoting parent-child conversations regarding sexual health, with attention to relational characteristics of the conversations, offers a promising approach to sexual health promotion and disease prevention for African American youth.