Objective: The purpose of this study was to examine the mediating effect of teaching flow on the relationship between director’s servant leadership and early childhood teachers’happiness. Methods: The subjects in this study were 241 early childhood teachers in Busan and South Gyeongsang Province in South Korea. Three different inventories were utilized. The Servant Leadership Scale, Teaching Flow Scale and Happiness Scale were used. As for data analysis, SPSS & AMOS 21.0 and PROCESS macro were utilized. Results: First, the director’s servant leadership, teaching flow and happiness of the teachers were all above average, and there was a significant positive correlation between their total scores of servant leadership, teaching flow and happiness. Second, The teaching flow was found to have a partial mediation effect on the on the relationship between director’s servant leadership and happiness of the early childhood teachers. Conclusion/Implications: These results indicate that effort to promote director’s servant leadership and teaching flow is needed to promote early childhood teachers’happiness.