A common phenomenon in the previous studies is that firm characteristics and corporate governance mechanisms were not combined in one study in Nigeria. This means that the contribution of either of the two in relationship to the effect of the other on financial performance of a firm is not investigated. Therefore, this study investigated the impact of firm characteristics and governance mechanisms on financial performance of listed building materials firms in Nigeria. The study formulated five hypotheses and used generalized least square multiple regression to analyze the secondary data extracted from the annual reports and accounts of the seven sampled firms for the period 2005 to 2014. The study found that leverage and firm size have significant impact on the financial performance of building materials firms in Nigeria. The study also found that liquidity, operating expenses and managerial shareholdings have no significant effect on the financial performance of the firms. In view of the findings, it is recommended among others that the management of listed building materials firms should reduce the level of leverage in their capital structure and focus more attention on equity financing, and decrease their assets and reduce the scope of their activities in order to decrease their size. The regulatory authority should determine the minimum and maximum percentage of firms' equity to be owned by management of listed firms in Nigeria.