Aim: To summarize and evaluate the existing evidence on the effectiveness of distal technology with regard to multiple health outcomes in people with diabetes. Methods: We searched PubMed, EMBASE and the Cochrane Database of Systematic Reviews from database inception to 31 August 2018 for systematic reviews and/or meta-analyses of studies that examined the impact of distal technology and reported any clinical or patient-related outcomes among people with type 1 or type 2 diabetes. Results: The umbrella review identified 95 reviews, including 162 meta-analyses with 46 unique outcomes. Evidence from meta-analyses of randomized controlled studies supports the use of distal technology, especially telehealth and mHealth (healthcare delivered by mobile technology), in people with diabetes for improving HbA1c values by 2–4 mmol/mol (0.2–0.4%). For other health outcomes, such as changes in fasting plasma glucose levels, risk of diabetic ketoacidosis or frequency of severe hypoglycaemia, the evidence was weaker. No evidence was reported for most patient-reported outcomes including quality of life, self-efficacy and medication-taking. The evidence base was poor, with most studies rated as low to very low quality. Conclusion: Distal technologies were associated with a modest improvement in glycaemic control, but it was unclear if they improved major clinical outcomes or were cost-effective in people with diabetes. More robust research to improve wider outcomes in people with diabetes is needed before such technologies can be recommended as part of routine care for any patient group.