The purpose of this study was to explore the factorial structures of workplace humor and mental health among preschool teachers, and to investigate the relationships between preschool teachers’workplace humor and mental health. The data were collected through questionnaires from a sample of 520 preschool teachers in southern Taiwan. The major instruments for this study included Preschool Teachers Humor Comprehension Sub-scale, Preschool Teachers Humor Preference Sub-scale, Preschool Teachers Humor Judgment Response Sub-scale, and Preschool Teachers Mental Health Scale. Structural equation modeling (SEM) was applied to make parameter estimations and model comparisons. The confirmatory factor analysis (CFA) supported a two-order factor model for both workplace humor and mental health in preschool teachers. Path analysis revealed a positive relationship between preschool teachers’workplace humor and mental health. The implications of this study to preschool teachers human resource management and future studies were discussed.