Stigma and discrimination towards people with mental health problems is a global issue, imposing a considerable public health burden in terms of social isolation, limited life chances, delayed help-seeking behaviour and stress. While numerous initiatives have been undertaken to address these issues, an evidence base for what works is still emerging. This paper explores the impact of 15 population-level awareness workshops delivered over a five-month period to 137 participants. These were employees drawn from workplaces identified as being important in the day-to-day lives of people with mental health problems. Evaluation approaches maximised specificity, sensitivity and anonymity and they assessed participant knowledge, attitude and behaviour. The workshops significantly improved participant knowledge. Attitude change was more complex with an overall significant improvement in attitudes, particularly in relation to unpredictability and recovery, but not dangerousness, which had more positive baseline attitudes. Social distance, a proxy for behavioural intent, had significant improvements in relation to 'moderate' social contact only. Qualitative feedback indicated that complex, unanticipated and positive messages had been absorbed by participants and influenced beliefs and behavioural intent. Service user narratives focusing on recovery were identified as the most valuable component of the intervention.