Accounting information utilized by management to convey firms' financial performance hold significant importance for various stakeholders, particularly potential and current investors, influencing their investment decisions. These financial performance metrics can directly impact the share prices of existing stocks. In this context, this research investigates the moderating influence of firm size on the relationship between financial performance indicators and share prices within quoted commercial banking institutions in Nigeria. The study aims to explore how earnings per share, and debt-to-equity ratio affect share prices, considering the influence of firm size on these relationships. The sample size consists of thirteen firms. Employing a two-model analytical approach, the study adopts pooled Ordinary Least Square multiple regression analysis, guided by the Breusch-Pagan LM Test for estimation. Findings from model I indicate that earnings per share exhibits a significant positive relationship with share prices, whereas the debt-to-equity ratio demonstrates a significant negative relationship with share prices. Model II results reveal that firm size has a significant positive moderating effect on the relationship between earnings per share and share prices. However, firm size shows an insignificant negative effect on the relationship between debt-to-equity ratio and share prices. The study recommends enhancing profitability to bolster earnings per share as it positively impacts share prices, and that Nigerian commercial banking institutions should resort to debt financing only as a last option, given its negative impact on share prices.