Happiness related to an individual’s happy perception, life satisfaction, and ability creates a balance between positive and negative feelings and leads to better functioning in life. Psychologists believe that the family plays a role in the explanation of happiness. In this regard, researchers have paid attention to the mother’s stereotypical beliefs and their effect on the mother’s behavior and her parenting style. The purpose of this research was to predict girls’ happiness based on their educational fields and their mothers’ gender serotypes. The statistical population included those student girls who were educated in high-school science and mathematics in Tehran in 2012. Random-cluster method was applied to select the samples. 243 participants completed a questionnaire on happiness and gender beliefs. Data were analyzed by hierarchical multiple regression. The results showed that mothers’ gender stereotype can predict happiness in girls. Also the educational field can predict girl’s happiness. The results of this research can be used by parents, educational psychologists and school counselors.