Purpose – This paper aims to examine the relationship between ethics programmes and ethical culture, and their impact on misconduct. Design/methodology/approach – A theoretical model which posits ethical culture to be a mediating variable in the relationship between ethics programmes and misconduct was tested using data from a national ethics survey of Korean public service organizations. Findings – The data indicates the relationship between ethics programmes and misconduct is fully mediated by ethical culture. Only two of the six elements of an ethics programme had a significant effect on misconduct before ethical culture was controlled for, and when ethical culture was controlled for, none of the elements had a significant impact on misconduct. The ethics programme did however appear to strengthen ethical culture, suggesting such programmes make an important contribution to reducing unethical behaviour in organizations. Research limitations/implications – Future research should examine the interaction of ethics programmes and ethical culture using longitudinal research designs, to obtain a better understanding of how programmes serve to strengthen ethical culture. Practical implications – The findings provide insights into the role of ethics programmes in improving ethical behaviour, suggesting resources should be deployed to those aspects of these programmes which serve to strengthen ethical culture. Originality/value – The paper provides clarification of the relationship between ethics programmes, ethical culture and misconduct, an important finding given the significant resources deployed by public service organizations to initiatives aimed at improving ethical behaviour.