Performance is the result of work in quality and quantity that can be achieved by an employee in carrying out tasks in accordance with the responsibilities given to him. Factors that can improve employee performance are work discipline, work environment, and work motivation. The purpose of this study was to analyze the effect of work discipline on employee performance, to analyze the influence of the work environment on employee performance, to analyze the effect of work motivation on employee performance, and to analyze work discipline, work environment, and work motivation simultaneously on employee performance. This type of research is explanatory research with a quantitative approach. This research was conducted on employees of PT. Macmahon Mining Services Martabe Project located in South Tapanuli, North Sumatra. The population in this study were all employees of PT. Macmahon Mining Services Martabe Project locations in South Tapanuli, North Sumatra totaling 673 with a sample of 87 respondents using a proportionate random sampling technique. The results showed 1) there was no significant positive influence of work discipline on employee performance, 2) there was a significant influence of work environment on employee performance, 3) there was a significant positive effect of work motivation on employee performance, and 4) there was a significant positive influence of work discipline, environment work, and motivation simultaneously on employee performance.

Keywords : Work Discipline, Work Environment, Work Motivation, and Employee Performance.