Research on the personality and its correlation to happiness found that personality is a strong predictor of happiness. Further studies also reveal that high self-esteem is found to be positively correlated with happiness. The purpose of this study was to examine the relationship between personality and happiness and specifically to examine how the correlation of both is mediated by\ self-esteem. This study hypothesises that personality correlates with happiness, and self-esteem mediate the correlation of personality with happiness. 118 participants of this study were adolescents to late adulthood in the ages ranged from 12 to 60 years. Data collected using Big Five inventory, personal self-esteem scale and mental health continuum-short form. The results show that the Big Five personality is correlated with both self-esteem and happiness. The result also proves that self-esteem mediates the relationship between the Big Five personality and the happiness.