This study proposes to examine the relationship between board diversity and organizational performance, with strategic decision-making quality as a moderating variable. It considers gender, age, educational and ethnic diversity in relation to financial and non-financial performance, with particular relevance to the Nigerian business context. Drawing on Agency Theory and Resource Dependence Theory, the study argues that diverse boards can enhance monitoring, broaden knowledge and improve access to resources, while also creating coordination and communication challenges. It proposes that high-quality strategic decision-making determines how effectively these diverse perspectives translate into organizational benefits. The study seeks to clarify inconsistent findings in existing literature and advance understanding of the conditions under which board diversity contributes to improved performance.