Objectives Ischaemic heart diseases (IHDs) are a leading cause of death worldwide. Although prescribing according to guidelines improves health outcomes, it remains suboptimal. We determined whether interventions targeted at healthcare professionals are effective to enhance prescribing and health outcomes in patients with IHDs. Methods We systematically searched PubMed and EMBASE for studies published between 1 January 2000 and 31 August 2017. We included original studies of interventions targeted at healthcare professionals to enhance prescribing guideline-recommended medications for IHDs. We only included randomised controlled trials (RCTs). Main outcomes were the proportion of eligible patients receiving guideline-recommended medications, the proportion of patients achieving target blood pressure and target low-density lipoprotein-cholesterol (LDL-C)/cholesterol level and mortality rate. Meta-analyses were performed using the inverse-variance method and the random effects model. The quality of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation approach. Results We included 13 studies, 4 RCTs (1869 patients) and 9 cluster RCTs (15 224 patients). 11 out of 13 studies were performed in North America and Europe. Interventions were of organisational or professional nature. The interventions significantly enhanced prescribing of statins/lipid-lowering agents (OR 1.23; 95% CI 1.07 to 1.42, P=0.004), but not other medications (aspirin/antiplatelet agents, beta-blockers, ACE inhibitors/angiotensin II receptor blockers and the composite of medications). There was no significant association between the interventions and improved health outcomes (target LDL-C and mortality) except for target blood pressure (OR 1.46; 95% CI 1.11 to 1.93; P=0.008). The evidence was of moderate or high quality for all outcomes. Conclusions Organisational and professional interventions improved prescribing of statins/lipid-lowering agents and target blood pressure in patients with IHDs but there was little evidence of change in other outcomes. PROSPERO registration number CRD42016039188 .