This study examined the relationship between transactional and transformational leadership styles and employee performance in the Nigerian oil and gas sector using Lubcon Oil and Orientry Ltd as study area. Survey design was adopted:, a sample size of 100 was used representing the total population of the study, convenient sampling used to select the study firms while stratified sampling was used to samples from all departments in the firms. Copies of questionnaire were administered to members of staff of Lubcon oil using purposive sampling. The data collected were analysed using descriptive statistics and correlation analysis. The analysis has shown that each of charisma, inspirational motivation and intellectual stimulation/individual consideration traits of transformational leadership style exerts positive and significant effect on both commitment and attitude of followers in the firm that adopts it most of the time, and a negative but insignificant effect on the commitment and also a positive but insignificant effect on their attitude in the firm that adopts it less of the time. On the other hand, each trait of transactional leadership style considered in this study, constructive/contingent reward and corrective and management by exception has strong positive and significant positive effect on attitude of employees, and a weak positive and insignificant effect of their commitment in the firm that adopts it most of the time, it also exerts weak positive but insignificant effect on both commitment and attitude of followers in the firm that adopts it little of the time. The study concludes that transformational leadership style is more appropriate in inducing employee performance in oil and gas firms than transactional leadership style. Consequently, the study recommends that oil and gas firms should adopt transformational leadership style but strategize to migrate to transactional leadership style during crisis and emergency situations.