The study of corporate governance and ethical issues in the business environment has called attention of researchers around the world. Moreover, the Securities and Exchange Commission (SEC), under the Sarbanes-Oxley Act of 2002, has compelled all publicly traded companies to publish an assessment of their internal controls to bring more transparency and ethics, as well as to promote improvements in companiesâ corporate governance practices. Against this background, this paper reports on a study aiming at discussing the ethical dimension in internal control systems when they are deemed as a part of the management control system. Content analysis of the literature on the eight major international models of internal control showed that only three of them (i.e., COCO, COSO ERM and King Report) are clearly concerned with the ethical dimension, and one of them, the COSO ERM, is the most complete and, therefore, the most appropriate model to account for ethics in a companyâs management control system. In conclusion, this paper points out that an appropriate internal control structure may contribute to (i) promote higher levels of ethics in business, (ii) achieve good levels of corporate governance, and (iii) improve managerial and operational efficiency and effectiveness.