Background: Cardiovascular disease is the leading cause of mortality for females globally, yet females are underrepresented in studies of acute coronary syndrome (ACS). Studies investigating sex-related differences in clinical outcomes of patients with non-ST elevation ACS (NSTEACS) have reported divergent results, and it is unknown whether long-term outcomes for older people with NSTEACS differ between males and females. Methods: The multi-centre prospective cohort study, ICON-1, consisted of patients aged ≥75 years undergoing coronary angiography following NSTEACS. The primary composite endpoint was all-cause mortality, myocardial infarction, unplanned revascularisation, stroke, and bleeding. We report outcomes at five-years by sex. Results: Of 264 patients, 102 (38.6%) females and 162 (61.4%) males completed the five-year follow-up and were included in the analytic cohort. At admission, females were older than males (82 ± 4.3 years vs 80.0 ± 4.1 years p = 0.018). Co-morbidity profile and GRACE score were similar between the groups. There were no differences in the provision of invasive or pharmacological treatments between sexes. At five-years, there were no association between sex and the primary outcome. Conclusion: In older adults with invasive treatment of NSTEACS, provision of guideline-indicated care and long-term clinical outcomes were similar between males and females.