Many studies have been performed on the interpretation of a person’s personality along the Five-factor model that includes the following traits: openness to experience, emotional stability, conscientiousness, extraversion and agreeableness. However, very little research has been done specifically on the personality of internal auditors. This study tries to establish insight into the personality of internal auditors by comparing them with other professionals. Based on a literature review and discussion, it is hypothesized whether or not the personality traits of internal auditors differ from those of other professionals. The hypotheses on each of the five factors have been tested for internal auditors and other professionals in The Netherlands. Results show that, for four personality traits, the internal auditor’s personality is significantly different from other professionals; only the trait agreeableness shows no significant difference. Limitations of the study lie in its exploratory nature.