Using the Triandis Model of Interpersonal Behavior (TIB), we considered the unique context of Mardi Gras, the annual festival in New Orleans, Louisiana, and how it might influence sexual behavior. This study utilized a two-stage, qualitative and quantitative methodological framework. Focus groups of past Mardi Gras participants were held to gather data to inform the development of the study instruments, and data were subsequently collected from 300 Mardi Gras participants in February 2004 using a pencil-and-paper questionnaire. For women, the TIB model did not significantly predict intentions to engage in sexual behavior at Mardi Gras. Cognitive beliefs and subjective social norms predicted intentions to engage in oral and vaginal sex among male participants. For men and women, peer sexual activity, intentions, and previous sexual experience predicted engaging in sexual behaviors at Mardi Gras. Situational conditions related to Mardi Gras culture predicted anal sex behavior. The TIB, as a guiding framework for the study, makes apparent the importance of cultural context when developing interventions related to sexuality that are to be implemented in a specific setting like Mardi Gras.