The aim or the present study was to examine the relative importance of financial education in school and families and dispositional factors (competitiveness, work mastery, meta-cognition) in predicting financial literacy among Finnish adolescents. The data on the 4328 Finnish 15-year-olds was drawn from the PISA 2018 assessment. Financial literacy was measured by tests, and financial education and dispositional factors were assessed by adolescent questionnaires. First, the results showed that financial education in school was positively associated with adolescents' financial literacy skills, whereas parental involvement in financial matters did not relate or related negatively to financial literacy scores. Second, dispositional factors, such as competitiveness, work mastery, and meta-cognition (effective strategies to understand/remember information, to summarize information, and to evaluate source credibility) were the strongest positive predictors of the financial literacy scores. Overall, the present study emphasizes that certain social factors (schools and families) and especially dispositional characteristics (personality/motivation and critical thinking/learning strategies) may shape the development of the financial skills of adolescents.