BACKGROUND: Adherence to drug and non-drug treatment for hypertension has a major socioeconomic impact, in addition to reducing the risk of cardiovascular events and morbidity and mortality. It is known that spirituality and religiosity can be incorporated into coping and managing hypertension. OBJECTIVE: To analyze possible factors associated with adherence to treatment in hypertensive patients and the role of spirituality/religiosity in this context. METHODS: Observational, cross-sectional, quantitative study, carried out with 237 hypertensive individuals monitored in a large Brazilian teaching hospital. Sociodemographic, clinical and lifestyle data were collected, in addition to measuring anthropometric data and performing a physical examination. To determine adherence to drug and non-drug treatment for hypertension, the QATSAH instrument was used and, to assess the level of spirituality/religiosity, the Duke Religion Index and the Brief Multidimensional Measure of Religiousness/Spirituality were applied. RESULTS: Higher levels of adherence to treatment were observed when aged ≥65 years, physically active, and who did not consume alcohol (p<
0.05). Regarding religiosity and spirituality, intrinsic religiosity (β = 0.24, 95%CI [0.22, 1.13], p = 0.004), values and beliefs (β = -0.18, 95%CI [-1.58, -0.20], p = 0.012), and forgiveness (β = 0.16, 95%CI [0.13, 1.19], p = 0.015) were statistically significant predictors of treatment adherence. Organizational religiosity, non-organizational religiosity, and daily spiritual experiences were not significant. CONCLUSION: Greater intrinsic religiosity, lower scores in Values and Beliefs and higher scores in Forgiveness increase the level of medication and non-medication adherence in hypertensive individuals.