Financial capability is an important competence for adolescents, and secondary school is a natural setting in which to deliver financial education courses. Currently, however, little empirical evidence has been published on the effects of in-school financial education on financial capability in adolescents. This pilot study brought together a randomized experimental design, a combination of local and non-local financial education courses, comprehensive measurements, and multi-level structural equation modeling for data analysis to evaluate the outcomes of a financial education project in a representative sample of Hong Kong adolescents. Results demonstrated that our financial intervention made a positive impact on objective financial knowledge and financial self-efficacy but a negative one on financial behaviors. Positive effects on financial self-efficacy were stronger in male adolescents than in females. Our findings represent an important contribution to the literature regarding financial education at the secondary school level. Copyright © 2019 Springer Nature B.V.