PurposeThe purpose of this study is to investigate the factors affecting the silence of internal auditors. To this end, the impacts of the perceived climate of silence, professional commitment, independence commitment, role conflict and role ambiguity on internal auditor silence have been investigated. Furthermore, the effects of role conflict and role ambiguity through independence commitment on internal auditor silence were investigated.Design/methodology/approachThe statistical population of the study consisted of Iranian internal auditors in 2021. The study used a self-administered survey of 217 internal auditors. In this research, a hierarchical component model in the partial least squares structural equation modeling analysis was used to examine the hypotheses.FindingsThe results of testing the hypotheses indicated that the perceived climate of silence and role ambiguity have positive effects, and professional commitment and independence commitment have negative effects on internal auditor silence. Furthermore, role conflict has an insignificant effect on internal auditor silence. In addition, role conflict and role ambiguity affect the internal auditor silence through the independence commitment.Originality/valueThis study examined the factors affecting the internal auditor silence by combining the construct of the perceived climate of silence that has been previously discussed in the field of management with the professional (professional commitment and independence commitment) and role (role conflict and role ambiguity) factors that are discussed in the internal audit profession. To the best of the author’s knowledge, this is the first study that examines the factors affecting internal auditor silence behavior. The importance of conducting this study is that it investigates a phenomenon among internal auditors that conflicts with the mission and origin of internal audit.