The relationship between perceived certainty and marijuana use was lowest among those who were strongly committed to the belief that marijuana use is a sin. For individuals who express the belief that marijuana use is a sin, the threat of punishment was not related to self-reported use. Legal sanctions were likely to be largely irrelevant as a deterrent among those who held strong, religiously based moral views opposing marijuana use. For individuals who were uncertain or strongly disagreed that marijuana use is a sin, the association between the perceived certainty of punishment and marijuana use was consistent with predictions from deterrence theory. The relationship between perceived certainty and marijuana use was lowest among those strongly committed to the belief that marijuana use is a sin. 5 notes, 4 tables, and 50 references