Abstract Aims Blood pressure control requires medication adherence and lifestyle modifications. Social cognitive theory suggests social support, psychological adaptation, and self-efficacy can reinforce lifestyle modifications. This study investigated if self-efficacy was a mediator between self-rated health status (SRHS), social support, depressive symptoms, anxiety, and self-care among patients with hypertension. Method and results This cross-sectional study recruited patients with primary hypertension by convenience sampling (N = 318) from an outpatient cardiology clinic. Data included participant characteristics and self-report scales for social support, SRHS, anxiety, depressive symptoms, Self-efficacy and self-care diet quality and weight management. We used path analysis to test the hypothesized model. The mean age of participants was 63.91 ± 11.80 years. Mean scale scores for social support and depressive symptoms were 54.23 ± 13.26 and 6.14 ± 3.14, respectively; SRHS was 66.91 ± 13.80, self-efficacy was 34.31 ± 11.62, self-care for diet quality and weight management were 36.50 ± 13.19 and 27.38 ± 8.64, respectively. Bootstrapping demonstrated self-efficacy was the mediator between social support and self-care for diet quality and weight management; depressive symptoms mediated the relationship between social support and self-efficacy. In addition, the variable of depressive symptoms was also a mediator between SRHS and self-efficacy. The final model showed SRHS, social support, depressive symptoms, and self-efficacy explained 28% of self-care. Conclusion Our findings suggest developing theory-based interventions for patients with hypertension that provide education and/or psychological support for increasing patients’ self-efficacy and reducing depressive symptoms simultaneously to facilitate their long-term self-care behaviours.