The objective of the research was to assess the effects of auditors' professional ethics on audit quality in Amhara Region audit firms. The researcher used a quantitative approach and explanatory research design. The data collection instrument was structured close ended survey questionnaires using the five point Likert scale adopted from different scholars in previous studies. The study used census survey sampling technique. The study descriptive and inferential statistics analysis technique. The findings of the study indicated that auditor’s competence, auditors' independence, auditor’s integrity, and confidentiality of information independent variables have positively and significantly effect on the audit quality by lowering cost of doing business and increase responsiveness, transparency and accountability in the companies under the study. But, auditor’s objectivity has no a significant influence on quality of audit in the study area. It is found that the auditor’s competence, auditors' independence, auditor’s integrity, and confidentiality of information were significant key drivers of audit quality of under the study. As a result, this is a clear signal to audit firms in the study area should not ignore these factors so as to keep and increase the quality of audit work. Professional auditors should be given training for the task ahead before being deployed to the field and induction training should be provided auditors on the fundamentals of carrying out a quality auditing exercise and the audit firms have to foster means to provide and receive accurate, reliable, and timely information to the audited companies under the study.