This study aims to analyze the effect of work-life balance on job satisfaction with happiness at work as a mediating variable among employees of the Agricultural Plant Protection Agency of West Nusa Tenggara Province. This research employed a quantitative approach with a causal associative research design. The population consisted of 62 employees, all of whom were selected as respondents using the census method. Data were collected through questionnaires, interviews, and documentation, while data analysis used Structural Equation Modeling (SEM) based on Partial Least Square (PLS). The results showed that work-life balance has a positive and significant effect on job satisfaction, work-life balance has a positive and significant effect on happiness at work, and happiness at work has a positive and significant effect on job satisfaction. In addition, happiness at work positively and significantly mediates the effect of work-life balance on job satisfaction. The findings suggest that the better the balance between employees' work and personal life, the higher their happiness at work, which ultimately improves job satisfaction.