Deliberate firesetting is a dangerous behavior that is associated with considerable costs annually. It has been estimated that young people under the age of 18 are responsible for a large proportion of all firesetting incidents. Moreover, firesetting has been linked to serious antisocial and aggressive behaviors and behavioral difficulties among juveniles and has been found to predict later delinquency, which makes this an important area to study. Some previous studies have found support for the importance of factors akin to self-control, e.g., impulsivity, for juvenile firesetting. This study applied an aspect of situational action theory (SAT), where self-control is viewed as part of crime propensity, but of lesser importance than morality, to the study of juvenile firesetting for the first time. Analyzing self-report data from two waves of the longitudinal Malmö Individual and Neighbourhood Development Study (MINDS), this study examines a key proposition of situational action theory, namely that morality is more important than self-control and that self-control is relevant in the explanation of crime (firesetting) only for individuals with lower levels of morality. The results indicate support for this proposition.