Background Task sharing for the management of hypertension could be useful for understaffed and resource-poor health systems. We assessed the effectiveness of task-sharing interventions in improving blood pressure control among adults in low-income and middle-income countries. Methods We searched the Cochrane Library, PubMed, Embase, and CINAHL for studies published up to December 2018. We included intervention studies involving a task-sharing strategy for management of blood pressure and other cardiovascular risk factors. We extracted data on population, interventions, blood pressure, and task sharing groups. We did a meta-analysis of randomised controlled trials. Findings We found 3012 references, of which 54 met the inclusion criteria initially. Another nine studies were included following an updated search. There were 43 trials and 20 before-and-after studies. We included 31 studies in our meta-analysis. Systolic blood pressure was decreased through task sharing in different groups of health-care workers: the mean difference was-5•34 mm Hg (95% CI-9•00 to-1•67, I²=84%) for task sharing with nurses,-8•12 mm Hg (-10•23 to-6•01, I²=57%) for pharmacists,-4•67 mm Hg (-7•09 to-2•24, I²=0%) for dietitians,-3•67 mm Hg (-4•58 to-2•77, I²=24%) for community health workers, and-4•85 mm Hg (-6•12 to-3•57, I²=76%) overall. We found a similar reduction in diastolic blood pressure (overall mean difference-2•92 mm Hg,-3•75 to-2•09, I²=80%). The overall quality of evidence based on GRADE criteria was moderate for systolic blood pressure, but low for diastolic blood pressure. Interpretation Task-sharing interventions are effective in reducing blood pressure. Long-term studies are needed to understand their potential impact on cardiovascular outcomes and mortality. Funding Wellcome Trust/DBT India Alliance.