Capital adequacy is important for the effective operation of any institution, particularly, its sustenance, viability and future growth. Banks as core financial institutions require sufficient capital base for its fund requirement and needs. Against this premise, banks and other financial institutions must keep balance between capital and available risk in its assets in order to reduce the likelihood of systemic crises, financial fragility and thus guarantee stability. This study empirically examines the impact of capital adequacy on the financial performance of banks in Nigeria. A sample of ten (10) listed banks on the basis of size and availability of data were examined over the period 2010 to 2017, using descriptive statistics, and multivariate panel data estimation technique, after conducting the Hausman, test of correlated random samples, wherein the fixed effect model was selected as the appropriate model. The empirical results revealed that banks’ capital adequacy ratio has a positive and significant impact on the financial performance of banks in Nigeria. Other variables found to be significant in the determination of the financial performance of banks in Nigeria are; bank size, bank loans and advances, debt ratio and growth rate of output. Against the backdrop of these findings, we recommend amongst others; sufficient capital base for banks, increased bank size through economies of scale measures, efficient deployment of bank resources, increased economic output (economic productive capacity) that will stimulate bank performance. These, will, in no doubt, reduce banks’ vulnerability to systemic crises and consequently enhance their stability for national growth through efficient financial intermediation.