Objective: The purpose of this study was to examine the effect of child care teachers' happiness and social support on job performance. Methods: The subjects were 380 teachers employed in child care centers and kindergartens in Gyeonggi Province. Self-report questionnaires were used to investigate teachers' happiness, social support and job performance. The data were analyzed by frequency, percent, Pearson's correlation and stepwise regression with the SPSS program. Results: The results of this study were as follow. First, teachers’ job performance was positively associated with teachers' happiness. The highest correlation sub-variable was purpose in life. Next were personal growth, self-acceptance, environmental mastery and autonomy. And the last was positive relationships with others. Teachers' job performance was positively associated with teachers' social support. The highest correlation sub-variable was evaluative support. Next were affective support and material support. And the last was informative support. Second, teachers' happiness and social support affected job performance. Evaluative support, which was a sub-variable of social support, affected job satisfaction. And personal growth, purpose in life, and self-acceptance, which were sub-variables of happiness, affected job satisfaction. Conclusion: This study revealed that teacher's happiness and social support were important factors for teachers job performance.