PurposeThe empirical study aims to examine the impact of board diversity with respect to gender and nationality on firm performance in an emerging economy. This research further splits the sample into family and non-family domains and investigates the diversity–performance nexus in isolation.Design/methodology/approachThe sample consists of 183 listed companies in Bangladesh over the period 2007 to 2017. This study employed the generalised method of moments (GMM) technique to address the possible endogeneity issue in the governance–performance connection. To underscore the strength of diversity, three distinctive assessment measures were used: percentage representation of females and foreign directors, the Blau index and the Shannon index.FindingsThe results for the full sample models reveal that board heterogeneity regarding both female and foreign directors positively and significantly influences firm performance as measured by return on assets (ROA). Further to this, female directors in family-owned businesses have a positive association with profitability, whereas foreign nationals demonstrate a significant positive association with performance in non-family firms. Additionally, at least three women directors are needed to make a positive difference in profitability; however, a sole director with foreign nationality is capable of demonstrating a similar impact on performance.Practical implicationsThe findings are significant for policymakers and organisations that advocate diversity on corporate boards of directors, and the minimum number of diverse board members needs to be considered depending on the identity to bring about a significant change in organisational outcome. Therefore, the findings of this study may be applied to other emerging economies with similar institutional characteristics.Originality/valueThis study reinforces the existing stock of knowledge on the impact of board diversity on the profitability of firms, especially in the context of an emerging economy – Bangladesh. Irrespective of the given backdrop, this study finds that both gender and nationality diversity in the case of Bangladesh is found to have a positive and significant effect on financial performance with respect to all the diversity metrics, i.e. the proportionate number of female and foreign directors on the boards, the Blau index and the Shannon index.