The cognitive-environmental model (CEM; M. Fishbein et al., 1991) was used to understand the unprotected sexual behaviors of 156 gay, lesbian, and bisexual youths. Unprotected anal sex among the males was associated directly with poor protection skills (e.g., incorrect use of barrier methods, such as condoms), poor intentions to use barrier methods, and poor norms by sexual partners concerning barrier methods. Furthermore, the association between low self-efficacy and increasing unprotected anal sex was attributed to poor intentions. Direct associations of unprotected oral sex with poor intentions and poor partner norms also emerged, as did an indirect relation between unprotected oral sex and low self-efficacy via poor intentions. These last 3 findings were replicated when examining unprotected oral or vaginal–digital sex among the females. Relations among the CEM factors supported some CEM-theoretical propositions.