A reliable banking system in developing economies like Nigeria is vital for economic progress as it facilitates the flow of funds to productive investment sectors. The capital adequacy requirement of banks is a crucial feature of the stability of the banks globally. Because of its importance, we have examined the antecedents to capital adequacy. We have used the data set of ten leading banks of Nigeria from 2007 to 2017. Our results indicate that ROA and loan to total assets are significantly associated with capital adequacy. However, we found that nonperforming loans and size are negatively associated with the capital adequacy. Our results do not support the association between macroeconomics variables and capital adequacy. Therefore, we recommend that all banking entities should reserve sufficient cash and cash equivalents as a percentage of deposits and apply aggressive risk management practices to reduce the magnitude of nonperforming loans. This study was restricted to one country. Future studies can be carried out in other countries. A comparative data set of more than one country may bring further insight into the phenomenonKeywords: Capital adequacy ratio, banks-specific determinants, macroeconomic determinants, Nigeria.