PurposeThird-party certifications promote firms' high standards and enhance their legitimacy and reputation, potentially positively impacting their performance, namely on exports.Design/methodology/approachThis paper studies the differences in firms' export performance between firms with and without the “SME Leader” label, a Portuguese firm-specific label. This study data set comprises data for 5.489 SMEs, for 2014–2020, where 2.950 firms obtained their certification during the period and 2.539 are non-certified control firms. The methodology adopted circumvents the traditional endogeneity problems in this type of study.FindingsThe results indicate that the “SME Leader” label does not directly improves a firm's export performance. Additionally, industry characteristics seem relevant for the relationship between SMEs' certification and their levels of internationalization.Originality/valueSince the study sample includes firms from all industrial sectors, this study results apply to various organizations.