The success and failure of every organisation either governmental or private establishment depends on the performance of every employees. Workplace stress has become one of the most controversial issues affecting employee performance in discharging their duties efficiently and effectively. This study examined the effect of workplace stress on employee performance: a study of Ethiope East and Ukwuani Local Government Areas of Delta State. The specific objectives were to determine the effects of workplace stress on employee performance, examine coping mechanisms employees adopt to manage stress, assess the role of organizational support on the relationship between stress and performance and recommend strategies for reducing workplace stress and improving employee performance. The study was guided by four research hypotheses. A descriptive survey research design was adopted, and data were collected using a structured questionnaire. The data collected were analyzed using descriptive statistics (mean and standard deviation), Pearson Product Moment Correlation, and multiple regression analysis at a 0.05 level of significance. The findings revealed a significant negative relationship between workplace stress and employee performance, indicating that increased stress reduces performance levels. The study also found a significant positive relationship between workplace stress and coping mechanisms, showing that employees adopt various strategies to manage stress. Furthermore, the results showed that organizational support significantly moderates the relationship between workplace stress and employee performance, reducing the negative impact of stress on performance. In addition, workplace stress and organizational support jointly had a significant effect on employee performance. The study also established that organizational stress-management strategies significantly enhance employee performance. The study concludes that workplace stress is a critical factor influencing employee performance, while organizational support and effective stress-management strategies serve as important buffers that improve employee productivity. It is recommended that organizations implement strong support systems, promote effective stress-management programs, and create a conducive work environment to enhance employee performance and well-being.