This study aims to understand the role that optimism could play in the context of a health asset approach to promote adolescent health-related quality of life (HRQOL). Adolescents (n = 948), between 11 and 16 years old from a medium-sized rural town in Sweden, answered questionnaires measuring optimism, pessimism, and HRQOL. The findings indicate a significant decrease in optimism and a significant increase in pessimism between early and mid adolescence. The study has allowed us to present associational evidence of the links between optimism and HRQOL. This infers the potential of an optimistic orientation about the future to function as a health asset during adolescence and by implication may provide additional intervention tools in the planning of health promotion strategies.