Efforts and policies of the Nigerian government to prevent Covid-19 and its spread have brought some challenges to Nigeria businesses which include reduction in business activities, volume and income, amongst other financial performance parameters. All government policies restricting movement and lockdowns had since been removed after the spread of the pandemic had been successfully contained. Whether the performances of these Nigeria companies had rebounded after the containment of the virus remains an empirical questions. Therefore, this study examined if there is any significant difference in the financial performance of listed firms in Nigeria for the pre and post COVID-19 period. The study covered a period of six years from 2017 to 2022 which were divided into Pre COVID-19 lockdown period and Post COVID-19 lockdown period. Secondary data were obtained from the annual reports of all the firms listed in Nigeria for the years 2017 to 2022. The study used a sample of 113 firms listed on the Nigerian Exchange. The research used the Wilcoxon signed rank test to conduct its analysis. The findings of the study showed that there was a negative and significant differences in the EPS (Z = -6.049, p =.000), ROA (Z = -6.821, p =.000) and ROE (Z = -6.912, p =.000) of the listed firms in Nigeria in the pre and post COVID-19 Pandemic periods. The study concluded that the EPS, ROA and ROE of the listed firms in Nigeria decreased in the post COVID-19 era as compare to period before the COVID-19. The study recommended that management of firms should consider ways of reducing operational costs without compromising quality. The study further recommended that firms should have plans in place that can help them deal in future with unexpected contingency like an outbreak and total lockdown.