The practice of managing employee relations in organizations has been observed to influence staff performance in one way or the other. For the practice to be more effective, leaders and managers are required to adopt effective respect, good channels of communication and build trust between individuals. The general objective of this study was to assess the effect of grievance handling procedures on employee performance of NCWSC Ltd. The Pluralist theory served as the primary theoretical framework for theoretical debate. 3239 middle and upper-level management staff members at NCWSC who were eligible for unionization made up the study's target population. Using a stratified selection strategy, 356 individuals were selected from the target population to serve as the sample, and data were gathered through the use of questionnaires as research instruments. A descriptive research design was employed in the study. a pilot study to confirm the reliability and validity of the research. The data were assessed using both descriptive and inferential statistics using SPSS version 22. Study findings were presented using graphs, tables and descriptive summaries. The study established that; Nairobi City Water and Sewerage Company's grievance resolution process is effective in settling disagreements, according to survey participants, who moderately agreed on an average mean score of 3.5266. With a correlation coefficient of r = 219 and a p-value of 008, grievance resolution demonstrated a modest but significant positive link, suggesting that there is a slight benefit to improving grievance resolution. Finally, a moderate regression effect (β =.187; p = 0.019) of grievance handling procedures on employee performance suggested that settling grievances has a beneficial impact on employee performance. The study concludes that grievance handling procedures have a positive influence on employee performance at Nairobi City Water and Sewerage company. The study found that poor co-ordination between part at NCWS in grievance resolutions. The study recommends fostering collaboration between key stakeholders, such as employees, management and labor unions, to create a transparent and structured grievance resolution process.