This study examines the impact of corporate governance mechanisms on the financial performance of private banks in Algeria. It specifically investigates the effects of board size, board meeting frequency, and bank size on return on equity (ROE). The analysis is based on a balanced panel dataset covering a sample of Algerian private banks over the 2012–2024 period. Panel-data econometric techniques were employed, and the random-effects model was selected following the application of the relevant specification and model-selection tests. The findings demonstrate that governance mechanisms are significantly associated with the financial performance of private banks. Board size has a positive effect on ROE, suggesting that broader representation and more diverse expertise within boards may strengthen oversight, strategic decision-making, and managerial effectiveness. Bank size also exerts a positive effect, indicating that larger private banks may benefit from economies of scale, resource diversification, stronger operational capacity, and improved market positioning. Conversely, board meeting frequency has a negative effect on ROE. This result implies that holding more meetings does not necessarily improve bank performance and may instead reflect reactive governance, coordination difficulties, higher administrative costs, or inefficiencies in decision-making. The overall model is statistically significant, and the included governance variables explain a meaningful proportion of the variation in bank performance. The study recommends strengthening governance practices through the effective composition of boards, improving the quality and productivity of board meetings, developing internal control and risk-management systems, and supporting the sustainable growth of private banks. These measures can enhance profitability, institutional resilience, and competitiveness within the Algerian banking sector.