Although attitudes strongly predict later sexual behaviors, few studies have investigated the factors that influence early adolescent attitudes toward sex. Using a general population sample of urban seventh-grade students (N = 1,736), we examined how supportive parenting, television viewing, perceived social norms, and having a friend and/or sibling who is a teen parent were uniquely associated with the probability and extent that early adolescents endorse favorable attitudes toward sexual activity. Supportive parenting was negatively associated with the probability of endorsement but not the strength of the endorsement. Perceived social norms and having a friend who is a teen parent were positively associated with both probability and strength of endorsement. Having a sibling who is a teen parent and greater television viewing were significantly and positively associated with the probability and extent of favorable attitudes toward sexual activity for females. Implications for prevention efforts targeting parenting and school policies are discussed.