Background and aims: Recently, positive psychology has received increasing importance, and research has shown that higher levels of happiness reduce the risk of mortality and morbidity. The aim of this study was to investigate the relationship between happiness and health behaviors in adolescents in Shahrekord. Methods: In this cross-sectional-analytical study conducted in 2018-2019, 428 first and second cycle secondary school students were enrolled and filled out the Oxford Happiness Questionnaire and Health Behavior Questionnaire. Then, data were analyzed by SPSS. Results: The mean age of the participants was 15.42±1.59 (range: 12-18) years, and 158 (36.9%) of them were boys. The mean score of happiness was 48.34±18.98 out of 87 (range: 0-87), which is high. The mean score of health behaviors was calculated to be 12.21±1.66 out of 16 (range: 8-16), which is moderate. In addition, the mean happiness score was significantly associated with gender (P=0.001), education level (P=0.01), family income (P=0.001), living status with parents (P=0.015), and personal estimate of happiness status (P=0.001). Moreover, the mean score of health behaviors had a significant association with gender, educational district, education level, parents’ education level, birth order, income, and personal estimate of happiness (P<0.05). Further, scores on happiness and health behaviors were positively correlated with each other (r=0.391, P=0.001) and negatively correlated with age (r=-0.139, P=0.004). Conclusion: The levels of happiness among adolescent students were relatively good, their levels of health behaviors were moderate, and both of them were associated with each other and with demographic and socioeconomic variables. Accordingly, happiness should be promoted in society, particularly in students, to achieve a higher level of health-promoting behaviors.