The purpose of this study was to determine if senior management support (SMSI) in Yemeni commercial banks mediates the association between internal audit function (IAF) quality characteristics and improved corporate governance effectiveness (CGE). Internal auditors, heads of internal audit, chairmen and participants in audit committees, CEOs, and financial management of Yemeni commercial banks were given a list of questions to answer. 158 full lists were obtained to evaluate after distributing the survey. For data analysis and hypothesis testing in this work, Smart PLS 3 was used. The study findings demonstrate a substantial relationship between CGE and IAF competence and due professional care (CPCI), IAF independence and objectivity (INOI), and IAF professional ethics (PEI). The outcomes of the study also demonstrate that there is no relationship between CGE and chief audit executive (CAE) Leadership Style (CLS). In terms of the moderate variable’s influence, the findings revealed that SMSI positively changes the link between CLS, CPCI, and corporate governance effectiveness. SMSI, on the other hand, has no influence on the link between INOI, PEI, and the efficacy of corporate governance. The findings add to the knowledge on IAF factors affecting the efficacy of CG and the role of SMSI in changing this relationship in developing countries such as Yemen. AcknowledgmentThe authors extend their appreciation to the deanship of scientific research at King Khalid University for funding this work through large groups project under grant number (RGP.2/189/44).