This study examines audit fee determinants among SMEs in Hanoi within an emerging-market context where financial transparency is increasingly vital for capital allocation and governance. Grounded in audit pricing theory and recent empirical evidence, the study develops a parsimonious model incorporating firm size, audit complexity, industry characteristics, legal form, auditor reputation, and reporting lag. Using data from 170 SMEs and 60 non-SME firms, the analysis applies descriptive statistics, correlation tests, and multiple regression to assess the relative influence of each factor. The findings indicate that firm size (total assets) and auditor reputation, particularly Big Four affiliation, are the most robust determinants of audit fees in SMEs. Among larger firms, revenue and organizational complexity (subsidiaries and branches) also become significant. In contrast, industry type, legal form, profitability (ROE), and working capital structure exhibit limited explanatory power within the SME sample. These results reaffirm the applicability of audit production theory in transitional economies while revealing institutional features specific to Vietnam’s audit market. The study contributes empirical evidence from a developing-country SME context and offers policy-relevant implications for regulators, audit practitioners, and SME managers concerned with audit quality and fee-setting practices.
