This chapter begins with a brief introduction to corporate governance and the crucial role played by the board of directors. It then offers the theoretical underpinnings for board diversity, before delving into the various dimensions of board diversity – age, expertise, cultural, ethnic, and especially gender diversity. The chapter then discusses key factors that can either promote or hinder board diversity and outlines the positive and negative impacts of diversity on board dynamics and functionalities. Next, the chapter highlights the effects board diversity has on firm outcomes such as financial performance, strategies, and innovations. The chapter concludes by discussing current trends in corporate board diversity and identifying potential areas for future research.