People's intuitions about the underlying causes of past and future actions might not be the same. In 3 studies, we demonstrate that people judge the same behavior as more intentional when it will be performed in the future than when it has been performed in the past. We found this temporal asymmetry in perceptions of both the strength of an individual's intention and the overall prevalence of intentional behavior in a population. Because of its heightened intentionality, people thought the same transgression deserved more severe punishment when it would occur in the future than when it did occur in the past. The difference in judgments of both intentionality and punishment was partly explained by the stronger emotional reactions that were elicited in response to future actions than in response to past actions. We consider the implications of this temporal asymmetry for legal decision making and theories of attribution more generally. (Contains 2 tables, 1 figure, and 3 footnotes.)