Despite ongoing regulatory efforts to enhance corporate governance in Nigeria, the financial performance of listed insurance firms remains inconsistent, raising questions about the effectiveness of board structures in ensuring accountability and strategic oversight. This study investigates the impact of board independence and gender diversity on the financial performance of listed insurance firms in Nigeria, using agency theory as its theoretical framework. Employing an ex-post facto design, the study analyses panel data from 2013 to 2023, sourced from audited financial statements of firms listed on the Nigerian Exchange Group. Financial performance is measured by net profit margin (NPM), with board independence (number of independent non-executive directors) and board gender diversity (number of female directors) as explanatory variables. Panel regression analysis reveals that board independence has a positive and statistically significant effect on NPM (p < 0.01), underscoring the importance of independent oversight in enhancing firm profitability. Conversely, board gender diversity shows a negative but statistically insignificant relationship with NPM (p > 0.05), suggesting that female representation has not yet yielded measurable financial benefits in this context, potentially due to cultural barriers and tokenism. The model explains only 5.2% of the variation in profitability, indicating that other factors significantly influence financial outcomes. The study concludes that strengthening the functional autonomy of independent directors is critical for improving financial performance, while targeted interventions are needed to enhance the influence of female directors. Recommendations include stricter enforcement of governance codes to ensure true independence, alongside leadership development programs to empower female directors for meaningful participation in board decision-making.