Background <p>Despite available treatments, uncontrolled hypertension (systolic/diastolic blood pressure ≥ 140/90 mmHg despite medication) remains prevalent, contributing significantly to mortality. However, global estimates of its prevalence vary widely. We aimed to determine the pooled global prevalence of uncontrolled hypertension among hypertensive patients.</p> Methods <p>We performed a systematic review and meta-analysis following PRISMA guidelines. PubMed, Web of Science, and Scopus were searched using a predesigned search strategy up to August 2024. The cross-sectional studies which reported the prevalence of uncontrolled hypertension prevalence in adults were included. Two reviewers independently screened studies, extracted data, and assessed bias risk using the JBI checklist. The heterogeneity was evaluated using I² statistics. The inverse variance method was used in meta-analysis, and the random-effects model at a 95% confidence interval (CI) was used to the report of the results.</p> Results <p>Out of 3,500 identified references, 200 studies met the eligibility criteria and were included in this review. The global pooled prevalence of uncontrolled hypertension was 54.6% (95% CI: 52.1–57.1; I² = 99.97%). In the WHO African region, the Americas, South-East Asia, European region, Eastern Mediterranean, and the Western Pacific Region the pooled prevalence was 59.4% (95% CI: 54.4, 64.5; I²=97.11%); 49.7% (95% CI: 42.4, 56.9; I² = 99.98%); 44.2% (95% CI: 35.6, 52.7; I² = 99.86%); 53.7% (95% CI: 49.8, 57.7; I² = 99.89%); 60.0% (95% CI: 54.1, 65.8; I² = 99.47%); and 58.8% (95% CI: 51.5, 66.0; I² = 99.96%) respectively.</p> Conclusion <p>Based on the results of this systematic review and meta-analysis, the global prevalence of uncontrolled hypertension was high. Based on the WHO regions, the highest and lowest prevalence was related to Eastern Mediterranean and South-East Asia respectively.</p>