Z1,M1, * L2, E1 AbstractBackground: The family is the smallest and almost fundamental community in all societies and cultures, and its mental health has influence on bigger communities. The happiness level is the most significant issue that is related to human health, especially women in the family whose happiness is related to their spouse's gratitude. The aim of this research was to evaluate the relationship between gratitude, happiness and mental health among women in military families. Materials and methods: In a correlation descriptive study, 302 women of 1400 wives were selected by multi-stage cluster sampling from military families in west of Tehran in 2013. To collect data, Goldberg's general health questionnaire and Oxford happiness questionnaire and Gratitude questionnaire was used. The data were analyzed using the Pierson’s correlation coefficient and Stepwise regression analysis. Results: There was a positive correlation between gratitude and happiness (p=0.01). There was a negative correlation (regarding the method of scoring) between gratitude, happiness and mental health among women in military families. Conclusion: The happiness parameter can predict the women’s mental health.