This study investigated the impact of capital structure on tax aggressiveness of listed manufacturing companies in Nigeria. The hypothesis was tested using data from the annual report of 39 manufacturing companies listed on the Nigerian Exchange Group from 2013 to 2022. The study was anchored on agency theory and trade-off theory. Diagnostic tests such as heteroskedasticity and the Hausman test were conducted. Applying Fixed Effects regression, the result shows that leverage and firm size negatively and significantly impact on tax aggressiveness. At the same time, external audit and revenue growth exert a positive and negative but insignificant influence on tax aggressiveness. Securities and Exchange Commission in Nigeria should encourage firms to maintain optimal leverage levels to mitigate tax aggressiveness, while ensuring transparency in external auditing to enhance tax compliance among listed manufacturing companies.