Moral development is one of the goals of physical education (PE). However, few programmes have been implemented to investigate how moral development is promoted in PE settings. This study was designed in order to explore the effectiveness of a six-week specially designed moral development intervention in the PE domain in high school students, and to examine whether moral reasoning differs between males and females. The intervention's design was based on the creation of a task-orientated motivation climate and on reciprocal teaching style. The sample (n = 157) was assigned to control (n = 80) and experimental (n = 77) groups. At the beginning and end of the intervention the Moral Judgment Test was applied. The results revealed that the experimental group exhibited statistically greater moral reasoning after the intervention compared to the control group; however, no significant gender differences were found. These findings indicate that an appropriate design of PE could support moral development. (Contains 1 table.)