Background The optimal duration of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention with stenting requires consideration of patient characteristics, and decision makers require a comprehensive overview of the evidence. Methods We performed an umbrella review of systematic reviews (SRs) of randomized controlled trials of extended DAPT (> 12 months) compared with DAPT for 6 to 12 months after percutaneous coronary intervention with stenting. Outcomes of interest were death, myocardial infarction (MI), stroke, stent thrombosis, major adverse cardiac and cerebrovascular events, bleeding, and urgent revascularization. We aimed to assess the evidence of benefits and harms among clinically important subgroups (eg, elderly patients, those with diabetes, prior MI, acute coronary syndrome). We assessed the quality of the included reviews by use of A Measurement Tool to Assess Systematic Reviews (AMSTAR). Results Sixteen SRs involving 8 randomized controlled trials were included. Most scored 7 or more points on the AMSTAR checklist. There was no significant difference in outcomes with extended DAPT compared with 6 months of DAPT in most SRs, with the exception of an increased risk of major bleeding. Compared with 12 months, extended DAPT may reduce the risk of MI and stent thrombosis; however, the findings were not consistent across all reviews. There have been conflicting reports of an increased risk of death with extended DAPT. Few SRs assessed outcomes among patient subgroups. Conclusions Extended DAPT may reduce the risk of MI and stent thrombosis but increase the risk of major bleeding and death. Whether the effects of extended DAPT are consistent across patient subgroups is unclear, and future SRs should address this knowledge gap.