This article reports a control study on the influence of a training program on attitude change towards people with mental illness. One hundred and seventeen students from 13 schools formed school-based mental health clubs, which composed the treatment group. They were given a mental health training program at different schools. The comparison group consisted of 102 secondary school students who had received no intervention. Students of both groups were assessed before the commencement, at the last session, and seven months after completion of the program with an OMICC (Opinion about Mental Illness in Chinese Community) scale developed by the authors. The study revealed significant positive changes, which could last a longer period of time, in specific attitudes on separatism and stigmatization of people with mental illness among students after the training program.