<p>This study assesses the effectiveness of an elective course in business ethics designed around a cooperative-learning approach and explores how this pedagogical method supports graduate students in practising ethical attitudes and behaviours. The research employs a mixed-method approach, integrating a quasi-experimental pre- and post-test study with an in-depth qualitative study based on focus groups. The quantitative study investigates the effectiveness of a business ethics course delivered within a university master’s program in improving various ethical outcomes, including moral efficacy, moral sensitivity, and moral motivation. In contrast, the focus groups explore how the cooperative-learning approach adopted within the course enhances the student’s learning process and the overall effectiveness of the course. The quantitative results demonstrate that the business ethics course effectively develops the students’ moral efficacy and moral motivation but not their moral sensitivity. The qualitative results indicated that the cooperative-learning approach contributes to achieving positive outcomes by favouring the motivational, relational, and cognitive dimensions of the student’s learning processes. The study contributes to the literature on business ethics education by providing a robust understanding of the effectiveness of business ethics programs in higher education and highlighting the role of the cooperative-learning pedagogical approach in developing graduate students’ ethical knowledge, skills, and behaviours. In addition, it showed that, despite the complexity of ethics, adopting a cooperative-learning approach in the business ethics course design improves the ability of future employees and managers to take responsibility for individual and collective actions.</p>