Background <p>Mexican American adolescents in the U.S. face disproportionately high rates of obesity. Familism, a core Mexican cultural value emphasizing family closeness, and parenting processes such as communication and monitoring are associated with adolescents’ weight-related behaviors such as diet, physical activity, sleep, screen time and weight outcomes.</p> Methods <p>Participants were 439 mother-adolescent dyads (47.2% boys) from the CHAMACOS cohort, a longitudinal study of Mexican-origin families in California’s Salinas Valley. Data were collected at the 14-year study visit. Adolescents reported on familism, maternal communication and monitoring, and their own weight-related behaviors. Anthropometric data were collected to calculate BMI percentiles. Structural equation modeling was used to test hypothesized relationships among variables and examine gender differences.</p> Results <p>Familism was positively associated with maternal communication and monitoring, as well as with adolescent physical activity and sleep, and negatively with screen time. Mother-youth communication was related to longer sleep duration, while maternal monitoring was not significantly related to any weight-related behaviors. Fruit and vegetable intake and sleep were negatively associated with weight status. Gender differences were observed: for girls, mother-daughter communication was linked to longer sleep duration, and for boys, familism was related to higher physical activity.</p> Conclusions <p>The results highlight significant associations between cultural values, maternal parenting, and healthy weight-related behaviors among Latino adolescents. These findings emphasize that incorporating gender-sensitive cultural and family dynamics may enhance the design of obesity prevention strategies for this population.</p>