Abstract Aims The optimal timing of an invasive strategy (IS) in non-ST-elevation acute coronary syndrome (NSTE-ACS) is controversial. Recent randomized controlled trials (RCTs) and long-term follow-up data have yet to be included in a contemporary meta-analysis. Methods and results A systematic review of RCTs that compared an early IS vs. delayed IS for NSTE-ACS was conducted by searching MEDLINE, Embase, and Cochrane Central Register of Controlled Trials. A meta-analysis was performed by pooling relative risks (RRs) using a random-effects model. The primary outcome was all-cause mortality. Secondary outcomes included myocardial infarction (MI), recurrent ischaemia, admission for heart failure (HF), repeat re-vascularization, major bleeding, stroke, and length of hospital stay. This study was registered with PROSPERO (CRD42021246131). Seventeen RCTs with outcome data from 10 209 patients were included. No significant differences in risk for all-cause mortality [RR: 0.90, 95% confidence interval (CI): 0.78–1.04], MI (RR: 0.86, 95% CI: 0.63–1.16), admission for HF (RR: 0.66, 95% CI: 0.43–1.03), repeat re-vascularization (RR: 1.04, 95% CI: 0.88–1.23), major bleeding (RR: 0.86, 95% CI: 0.68–1.09), or stroke (RR: 0.95, 95% CI: 0.59–1.54) were observed. Recurrent ischaemia (RR: 0.57, 95% CI: 0.40–0.81) and length of stay (median difference: −22 h, 95% CI: −36.7 to −7.5 h) were reduced with an early IS. Conclusion In all-comers with NSTE-ACS, an early IS does not reduce all-cause mortality, MI, admission for HF, repeat re-vascularization, or increase major bleeding or stroke when compared with a delayed IS. Risk of recurrent ischaemia and length of stay are significantly reduced with an early IS.