Background: Mental disorder-related stigma, usually experienced through prejudice or discrimination, can gravely impact an individuals’ quality of life. Nurses play an important role in the advocacy and treatment of people with mental disorders. It is therefore important that their attitudes, behaviour and knowledge regarding people with mental disorders are understood within their cultural context and that they are educated appropriately during their early student years. Aim: To develop and evaluate the usability, feasibility and effectiveness of a media-based educational intervention (film) against education as usual practice (lecture), in reducing mental disorder-related stigma in terms of attitudes, knowledge and intended behaviour amongst Saudi nursing students. Methods: The research study draws upon the first two phases (development and feasibility/piloting) of the Medical Research Council’s framework for the development and evaluation of complex interventions. A mixed-methods research design was used, entailing: theoretical and systematic reviews of evidence-based literature; modelling, developing and refining of the intervention-prototype and outcome measures; usability testing with stakeholders; feasibility testing of the refined intervention through an exploratory randomised controlled trial and a qualitative evaluation study to assess the preliminary effectiveness of the intervention. Outcomes were measured at three time points: baseline, immediately post-intervention and at three months follow-up. Results: Outcome measures improved significantly for both intervention conditions in comparison to the control group; however, there was no significant difference in effectiveness between the intervention conditions. The film intervention was more effective in the 3rd-year and the lecture in the 4th-year nursing students. The findings of the qualitative evaluation study showed that student nurses expressed a preference for the inclusion of service users’ personal testimonies in the educational intervention. They were also more likely to remember this component of the intervention than other aspects when in clinical practice. Conclusion: This study contributes to a growing literature supporting the use of filmed social contact interventions containing personal testimonies as an effective educational option to reduce mental disorder-related stigma amongst healthcare students.