Background: Poorly controlled hypertension may lead to several serious health problems, including stroke, aneurysms, coronary artery disease, kidney disease and peripheral artery disease. Objectives: This study aimed at exploring the magnitude of the problem of non-compliance with antihypertensive drugs among patients in Saudi Arabia and identifying the associated factors. Subjects and Methods: a cross-sectional study was carried out during the period January to August 2018 through social media sites including a sample of adult patients from different regions of the kingdom (Saudi and none-Saudi). Data were collected online through a questionnaire. The questionnaire included socio-demographic characteristics of hypertensive patients, history of smoking, and hypertension-related history. Adherence of patients to anti- hypertensive drugs was assessed utilizing an 8-item modified Morisky Medication Adherence Scale (8-MMMAS). Results: The study included 267 hypertensive patients. About half of them (48.5%) aged over 50 years. More than half were females (58%), high educated (62.3%) and employed (46.7%). Approaching half of them, 42% has health insurance and 6 years or more of hypertension (47.6%). About two-thirds of them (68.8%) reported history of taking between one and three drugs/day and one dose of antihypertensive medication/day (64.8%). High level of compliance with anti-hypertensive medications was observed among 6.2% of patients whereas medium and low levels were observed among 67.4% and 26.4% of them. High level of compliance was reported among patients aged over 50 years (p<0.001), females (0.033), widowed (0.001) and those haven't history of chronic diseases (p<0.001). Conclusion: high compliance to anti-hypertensive medications in Saudi Arabia is low, particularly among male and young patients.