Life satisfaction has been studied extensively in adults and to a lesser extent in adolescents. Consequently, less is known about well-being and what leads to life satisfaction in adolescence. The purpose of the present study was to investigate adolescent life satisfaction. Based on self-reports, short-term and long-term effects of various factors on life satisfaction were investigated. Specifically, the study aimed to longitudinally examine the extent to which body image, negative emotionality, social support from peers, and positive and negative life events predicted life satisfaction. Using two waves of data from the Tracking Opportunities and Problems in Childhood and Adolescence (TOPP) study, the current study used multiple regression analyses to explore longitudinal relations between personal and environmental factors, and life satisfaction. A population-based sample of Norwegian adolescents completed survey questionnaires at ages 12-13 (N=594) and 16-17 (N=375). The results showed that body image, negative emotionality and social support predicted life satisfaction, whereas life events did not. Findings also revealed that long-term effects were mediated through short-term effects and that gender differences were relatively small. The results underline the importance of promotion efforts aimed at strengthening factors associated with adolescent life satisfaction, such as body satisfaction and peer support.