Purpose This study aims to determine the relationship between health literacy and the self-care of hypertension in older adults in five regions in Jordan. Design/methodology/approach A cross-sectional study was conducted with 1,100 older adult patients with hypertension who had follow-ups in cardiac clinics of the five biggest hospitals in five regions of Jordan. The research instruments included a Health Literacy Questionnaire (CHEWQ) and the self-care of hypertension inventory. Findings The average health literacy score was 8.52 ± 1.6, indicating inadequate health literacy, while their self-care of hypertension score was 42.33 ± 10.9, indicating low self-care. Inadequate health literacy and factors such as marital status, education level, income and overall health status were linked to poor self-care of hypertension (p < 0.05). Practical implications This study suggests that there is a need to assess the effectiveness of various health literacy interventions, such as educational programs and customized communication strategies, in enhancing self-care behaviors across diverse populations, particularly among the elderly. Originality/value The study findings highlight the need for nursing interventions aimed at improving health literacy to enhance the ability of older adults in Jordan to manage their hypertension.