The study examined the effect of ownership structure on the earnings management of oil and gas firms in Nigeria. The study was motivated by a slight decrease in revenue from the oil and gas contribution to national income. Four proxies of ownership structure were employed in the study; that include ownership structure, managerial ownership, institutional ownership and foreign ownership while discretionary accruals proxy earnings management. The study analyzed a total of 10 listed companies over 10 years observation obtained from annual reports of the affected firms between the period of 2014-2023. Panel data regression was employed as model of analyses. Findings from the study indicate a significant and positive relationship between ownership concentration, institutional ownership and earnings management, while foreign ownership has a significant but negative association with earnings management. Managerial ownership is not significant in the model. The study, therefore, recommends a downward review of both ownership concentration share proportion as well as that of institutional ownership, enhancement of managerial ownership and increase review of foreign ownership which should be guided by a policy directive.