Background <p>Improving blood pressure (BP) control is of major importance among patients with diabetes, due to their high risk of micro- and macrovascular complications. Community-based models of care with the involvement of pharmacists and other nonphysician healthcare providers can help manage hypertension. We aimed to estimate the effectiveness of pharmacist interventions, alone or in collaboration, on BP among outpatients with diabetes and hypertension.</p> Methods <p>We conducted systematic searches of randomized controlled trials (RCTs) assessing the effect of pharmacist interventions on BP among outpatients with hypertension and diabetes compared to usual care. The outcome was the systolic and diastolic BP change or BP control. We performed a meta-analysis with a random effects model to estimate mean differences in BP or relative risk of BP control, with 95% confidence intervals (CIs). The protocol was registered in PROSPERO (CRD42021279751) and published in an open-access peer-reviewed journal.</p> Results <p>Out of 2330 study records identified by electronic database searching, we included 12 studies in the systematic review, with 5,256 participants (control 2,906; intervention 2,350), published between 2002 and 2022. In comparison with usual care, mean systolic and diastolic BP were reduced after pharmacist interventions by -7.2 mmHg (95% CI: -12.5 to -1.9; I² = 87%) and − 4.1 mmHg (95% CI: -6.9 to -1.4; I² = 0%), respectively. BP control was improved after pharmacist intervention (relative risk: 1.76, 95% CI: 1.39 to 2.24; I² = 50%). Analyses restricted to relatively large or high-quality studies yielded consistent but slightly lower estimates.</p> Conclusion <p>Pharmacist interventions improve BP control in patients with diabetes and hypertension.</p> PROSPERO registration number <p>CRD42021279751.</p>