Purpose – This paper aims to examine and compare the quality of mandatory joint audits among six joint audit pair types within and across listed nonfinancial companies in the European Union (France) and the MENA region (Morocco and Tunisia). Design/methodology/approach – A multivariate regression model examines variations in audit quality across six auditor-pair categories using a sample of 440 nonfinancial firms from 2014 to 2023, yielding 4, 400 firm-year observations: 3, 590 from France, 510 from Morocco and 300 from Tunisia. Findings – The analysis indicates that there are no statistically significant differences in the quality of mandatory joint audits between most joint audit pair categories within and across countries. These results indicate that mandatory joint auditing may reduce variation in audit quality across pairs, both within and across countries. An additional analysis of the effect of audited firm size shows consistent outcomes for small, medium and especially larger firms. In addition, including at least one industry-specialized auditor in most joint audit pairs does not significantly affect audit quality. Practical implications – This study provides valuable insights for regulators, policymakers, audit firms and companies by offering clear evidence on how auditor-pair composition, firm size and industry specialization affect the quality of mandatory joint audits within and across countries, thereby supporting the development of effective regulations in both developed and developing markets. Originality/value – To the best of the authors' knowledge, this study is among the first to examine and compare the quality of mandatory joint audits across joint audit pairs in developed and emerging economies, using a six-category pairwise classification, recent data and analysis of firm size and industry specialization.