This research aims to explore the impact of board gender diversity on the relationship between ownership structure and firm performance. The research employs sample of 26 non- financial firms listed on the S&P EGX 30 ESG index for the period of 2016-2021. The study utilized accounting-based measures (ROA & ROE) and market-based measure (EPS) to evaluate the firms' performance, ownership identity (family, foreign, institutional, managerial) to evaluate the firm's ownership structure as well as leverage, board independence, firm size, board meetings, and board size as control variables. The research findings indicated that ownership structure have significant positive impact on the firm performance (using both accounting based and market-based measures). Moreover, board gender diversity moderates the relationship between ownership structure and firm performance. The study findings have an important implication for regulators they are advised to establish policies aimed at empowering women in firms board of directors and guidelines that steer the ownership and board structure in the ideal manner to enhance firm performance.