Purpose This paper explores the ethical decision making of internal auditors and the impact of corporate governance mechanisms thereon. It also explores whether ethical decision making is influenced by years of experience in internal auditing. Design/methodology/approach Sixty-six internal auditors were presented with five ethical dilemmas. For each scenario, a key element of corporate governance was manipulated to assess its impact on ethical decision making. These were audit committee support; management integrity regarding accounting policies; management integrity regarding pressure on internal audit; external auditor characteristics; and organisational code of conduct. Findings Participants were generally sensitive to ethical dilemmas but were not always confident that their peers would act ethically. A higher quality external audit function was positively associated with internal auditors’ ethical decision making. However, the strength of other governance mechanisms did not appear to influence ethical decision making. Finally, more experienced internal auditors adopted a more ethical stance in some cases. Research limitations/implications Our sample was self-selected and may not be representative of internal auditors in general. Our lack of significant results may be due to insufficient variability in our manipulations and/or an oversimplification of reality in our scenarios. Practical implications The study has implications for the internal audit profession with respect to training and the provision of support mechanisms to strengthen the ability of internal auditors to withstand pressure when dealing with ethical dilemmas. Originality/value This paper is the first to study whether the strength of other governance mechanisms influence internal auditors’ ethical decision making
