This study was based on the manipulation of accounting figures and the financial performance of listed firms in Nigeria between the periods of 2007-2019 (Thirteen years). Ninety (90) firms were drawn as research samples among one hundred and nine (109) listed non-financial firms in Nigeria. The study was done quantitatively and conducted from secondary data obtained from the annual reports of various firms. Descriptive statistics and correlation analysis were used to determine the nature of the relationship between the independent and dependent variables. Given the hypothesis formulated for this research, the method of model estimation employed was a panel regression analysis with the aid of Stata 14 software. The findings revealed that some manipulation techniques such as incorrect asset valuation and timing of assets transaction impact positively on return on assets, thereby justifying the act, albeit unethical. Other techniques such as revenue falsification and understatement of liabilities were seen to negatively impact the return on assets. The study recommends among others, that investors should employ the services of competent financial analysts to scrutinize financial statements of firms they want to invest in.