African-American adolescents (N = 295) reporting high or low levels of social support completed measures of AIDS knowledge, health locus of control attitudes toward condoms, self-reported sexual behavior for the preceding 12 months perceptions of personal HIV risk, and self- and resonse-efficacy ratings. Adolescents with less social support were less knowledgeable about AIDS, held more negative attitudes toward condoms, and were lower in self efficacy than adolescents with higher levels of social support. Adolescents with fewer social supports also were significantly more likely to engage in casual sex, reported more nonmonogomous partners, more frequent coercions into unwanted sexual activity and higher rates of sexually transmitted diseases African-American males with low social support scores engaged in more frequent unprotected sexual activity with a larger number of sex partners and used condoms less often. The implications of these result for prevention efforts targeting minority adolescents are discussed.