<p>Professional ethics is a foundational element in the accounting and auditing professions, receiving sustained attention in academic research and practical implementation. In light of recurrent financial scandals linked to unethical conduct, stakeholders, including higher education institutions, policymakers, and enterprises, have intensified efforts to reinforce ethical standards for current and future professionals. This paper identifies factors affecting accounting and auditing students’ perception of professional ethics. The study uses the Extended Theory of Planned Behavior (ETPB) to investigate students’ intentions to engage in unethical behavior across two experimental scenarios: confidentiality and charging personal costs to an employer’s accounts. The study analyzes survey responses from 214 accounting and auditing students at several universities in the Hanoi area by employing a quantitative approach. The findings show that four explanatory variables (attitude toward unethical behavior, norms, perceived behavioral control, and moral obligation) significantly affect intentions to violate the students’ professional ethics. Among these, moral obligation emerges as the most influential predictor. The results support ETPB as a reasonable basis for understanding future accounting and auditing professionals’ perceptions of ethical behavior. The findings also highlight the impact of ETPB factors in the context of Vietnamese culture on unethical behavioral intention. Notably, the study underscores the strategic role of ethics education in supporting sustainable development goals by cultivating a responsible, transparent, and ethically grounded accounting profession.</p>