This study investigates the effect of corporate governance mechanisms on the risk-taking behaviour of Nigerian commercial banking firms, with risk-taking proxied by the non-performing loan ratio (NPL). The research is anchored in Agency Theory, complemented by Risk-Shifting and Regulatory Forbearance Theories, which explain how separation of ownership and control, weak oversight, and lenient regulatory intervention can incentivize excessive risk-taking. Employing a panel data approach covering 13 commercial banking firms over the period under review, the study applies pooled OLS, fixed effects, and random effects regression models, supported by unit root and correlation analyses to ensure data suitability and robustness. Descriptive statistics reveal elevated NPLs averaging 8.94%, substantial variation in board size (mean 12 directors), and a predominance of non-executive directors (average 64%), highlighting heterogeneity in governance structures. Correlation analysis indicates positive but weak associations between governance variables and NPLs, while panel regression results demonstrate that board size, percentage of executive directors, and percentage of non-executive directors do not have statistically significant effects on credit risk. These findings suggest a disconnect between formal board structures and effective risk management, implying that internal governance mechanisms alone are insufficient to mitigate bank risk in Nigeria. The study concludes that regulatory compliance, ownership structures, and behavioural governance factors play more critical roles in shaping risk-taking. Based on the findings, it is recommended that regulators strengthen enforcement of governance codes, banks align ownership and executive incentives with prudent risk behaviour, and boards enhance substantive effectiveness through capacity-building, risk oversight, and active strategic participation.