This study investigates the interaction effects of locus of control, a personality variable, and ethical reasoning on the behaviour of auditors in an audit conflict situation. Eighty experienced auditors from a sample of Big Six and Non-Big Six CPA firms in Hong Kong were provided with a case study involving an audit conflict situation and were asked to state the extent to which they would accede to the client's request. Subjects were also administered Rotter's Locus of Control Scale and the Defining Issues Test (DIT) to measure ethical reasoning. Analyses of the data using multiple regression found that ethical reasoning moderated the relationship between locus of control and the auditors' responses to accede to client's request in an audit conflict situation. An implication of these results is that the explicit recognition of both locus of control and ethical reasoning provides a better explanation for differences in auditors' ethical decision making.