Background: African-American adolescent females are disproportionately affected by the HIV epidemic in the United States. One important potential, yet understudied, protective influence that may reduce African-American adolescents' HIV risk behavior is their involvement in social organizations. Objective: To examine the association between high-risk African-American adolescent females' activity in social organizations and their recent HIV-associated sexual risk behavior. Methods: Sexually active, African-American females (N = 522) were recruited from schools and adolescent medicine clinics in low-income neighborhoods of Birmingham, Alabama. Adolescents completed a self-administered survey and face-to-face interview. Adolescents' participation in Black social organizations was assessed. Measures of HIV protective behavior were also assessed. Bivariate analysis was followed by logistic regression to calculate adjusted odds ratios (AOR) for the outcomes. Results: Adolescents not belonging to social organizations were about 1.6 times more likely to report recent acquiescence to unwanted sex without a condom, 1.9 times more likely to report that their current steady sex partner had other partners, and 1.9 times more likely to score low on the measure of sex-related communication with parents. Discussion: Findings from controlled analyses suggest that community-based Black social organizations may be an important venue for protecting African-American adolescent females from having sex with a partner who has concurrent partners, and from having unwanted sex without a condom. Participation in Black social organizations was also associated with more frequent interaction between adolescents and their parents about sex-related issues such as HIV prevention. Models of HIV prevention that promote community involvement may be an under-utilized intervention modality with high potential impact.