Purpose. This study was done to identify and test a model of the psychosocial variables that influence adherence to therapeutic regimens in patients with hypertension. Method. A convenience sample of 219 patients with hypertension who were enrolled in an outpatient clinic of a cardiovascular center in Korea participated in the study. They completed self-administered questionnaires anonymously. The questionnaire was based on the Social Action Theory model and a literature review. The explanatory model was constructed and tested using structural equation modeling in order to examine the effects within the model. Results. The results of this study showed that perceived self-efficacy was the strongest factor influencing patient adherence in this sample. Adherence to therapeutic regimens in patients with hypertension was influenced by self-efficacy, patient-provider relationship, social support, and depression. Conclusions. Adherence to therapeutic regimens in patients with hypertension was most strongly influenced by self-efficacy. These findings suggest that nursing interventions to promote patient adherence should focus on the promotion of self-efficacy including improvement in patient-provider relationship and social support, and reduction in depression.