Employee performance is influenced by workload, work environment, and work stress. One of the business phenomena as seen in the current news is the declining of employee performance. One of the phenomena as seen form a case study the employee performance is declining from 80% in 2015 to 70% in 2021, which is below the minimum required rate of 85%. However, there is still limited research looking at employee performance as seen from the workload and work environment with the moderating impact of work stress. This research is filling up the gap by analyzing the impact of workload and work environment toward employee performance, moderated by work stress. The employees of PT Matra Perkasa Utama were used as respondents in this study and used a questionnaire survey in June 2023. The data were processed with the partial least square structural equation model (PLS-SEM). The test's findings demonstrated that there are positive correlation between work environment and work stress. It is also concluded that workload has significant influence to employee performance. However there are no mediating effects of work stress on the influence of workload and work environment toward employee performance. As implications, it was critical for the company to provide conducive work environment, placement of employees according their ability and skill and also effective allocation of workloads. The limitation of this paper lies in the limited amount of empirical data. Further research should be conducted empirically with more sets of data.