The paper aims to identify how board diversity, measured as women, foreign- and state- representatives on boards of directors, influences company’s CSR disclosure and firm performance in the context of the transitional Russian economy. The focus on Russian companies brings new insights on this type of relationships and opens the discussion about the effectiveness of corporate governance systems in emerging and transition economies. Stakeholder and agency theories are used for developing the theoretical background. Empirical analysis is conducted on a sample of 223 publicly listed Russian companies for the period 2012-2017. We find that different dimensions of board diversity affect CSR disclosure and firm performance differently. Thus, women representatives on boards negatively affect CSR disclosure while having a positive effect on firm performance. Foreign members on boards of directors enhance CSR disclosure while not having any statistically significant effect on firm performance. State representatives on boards positively influence CSR disclosure while negatively affecting firm performance. Explanations for these findings are deeply rooted in social norms and standards in transition of the corporate governance system in Russia.