This paper reports on a study that employed a theory-based approach in the form of a learning study to enhance a domain-specific generic capability, financial literacy, of Grade 12 students to empower them to make informed and independent financial decisions. Financial literacy is seen in this study as a function of student understanding of a limited set of interrelated economic concepts that can be used as tools to assess financial situations and make sound financial decisions. Twelve teachers participated in the study. Six worked together in a learning study group and drew on a particular theory of learning in planning and carrying out lessons designed to serve the learning aims, whereas the other six worked collaboratively in a lesson study group. To evaluate the effectiveness of the two learning conditions created by the two groups, 193 students answered questions on complex, everyday financial situations in four tests: a pretest, a posttest following the research lessons, and delayed posttests 6 weeks and 6 months after instruction. The results showed that students in the learning study group outperformed their counterparts in the lesson study group in all three post-lesson tests, and that the inter-group performance gap was maintained or widened over time.