Within the context of Rosenbaum's theory of learned resourcefulness, this correlational study examined the relationships among family functioning, self-esteem, and resourceful coping in Thai adolescents with asthma. A convenience sample of 132 Thai adolescents (aged 12-17 years) with asthma was recruited from the outpatient asthma clinics of four hospitals in Bangkok. Self-administered questionnaires included an assessment of demographic information and asthma status, the revised Family APGAR, the Rosenberg Self-Esteem Scale, and the Children's Self-Control Scale. Hierarchical multiple regression analysis was used to examine the relationships among variables. Effective family functioning had a significant positive effect on self-esteem (beta = .27, p < .01) and resourceful coping (beta = .30, p < .01), controlling for gender and age. However, self-esteem was not significantly correlated with resourceful coping (beta = .15, p = .08). The findings suggest that nursing interventions should take into account the role of family functioning in promoting self-esteem and resourceful coping in Thai adolescents with asthma. Recommendations for future research include replication of the study with a larger sample of adolescents with asthma and with adolescents with other chronic illnesses.