Very little is known about what factors predict variations in responses to positive events among youth. Consequently we examined young adolescents’ positive emotional reactions and their savoring and dampening responses to their most intense positive event across a four-day period. The investigated predictors were parent-reported adolescent temperament adolescent-reported attachment security with mothers and fathers and researcher-coded event characteristics. The sample was 56 youth (31 boys 10–14 years of age). More support was found for temperament than attachment. Specifically effortful control predicted more savoring and sustained positive affect (PA) about the events whereas negative emotionality predicted more dampening. Adolescents’ reports of more secure attachment to fathers were marginally linked to more savoring of their positive event. Girls reported higher levels of initial PA yet endorsed more dampening responses than boys. Event type (interpersonal vs. not) was unrelated to responses to the events. Overall this study offers new information on the development of PA regulation and responses to positive events in youth.