The authors examined the effect of school-related social support from teachers, classmates, and parents on students' life satisfaction that school satisfaction, scholastic competence, and general self-efficacy, respectively, mediated. The authors based the analyses on data from a nationally representative sample of 13- and 15-year-old students (N = 3,358) from the Norwegian part of the 6th World Health Organization international survey of "Health Behaviour in School-Aged Children" (C. Currie et al., 2004; T. Torsheim, O. Samdal, B. Wold, & J. Hetland, 2004). The authors used the analytic approach of structural equation modeling through the statistical program Mplus (5th ed.; L. K. Muthen & B. O. Muthen, 2007). Results confirmed the importance of self-related domains, such as general self-efficacy, to students' life satisfaction. Teacher support strongly related to school satisfaction. On the basis of significance tests between correlations, school satisfaction more strongly related to girls' life satisfaction than to that of boys. (Contains 4 tables and 2 figures.)