Abstract: This study examined the relationship between sources of stress at work and Ground service agents’ level of stress. Of the 150 Thai full-time Ground service agents based at Bangkok station who received the survey, 114 returned it for a 76% response rate. Stepwise regression analysis was used to determine the impact of Five Sources of Stress at work on the level of employees’ stress level. The findings revealed that all aspects of five stress sources’ dimensions including Job Characteristics; Role of employee participation; Progression of careers; Relationship in the workplace; Organizational structure and climate were positively correlated with the level of stress among Ground service agents. In the regression analysis, it was found that Role of employee participation and Relationship in the workplace were the factors that most significantly affected stress level at work. The influence of working factors on employees’ stress level who work in aviation industry was discussed in light of these findings.