Background/Objectives: Recent studies show conflicting results regarding sex-related differences in outcomes following aortic surgery. This study primarily evaluated 20-year mortality rates, along with 30-day and one- and five-year rates, and postoperative complications in female and male patients who underwent elective and acute ascending aortic surgery at a tertiary care centre. Methods: This retrospective observational study analysed data from 676 adult patients who underwent ascending aortic surgery in Amsterdam UMC, between January 2001 and December 2020. Descriptive statistics, Fisher’s Exact test, Kaplan–Meier survival analysis, and logistic regression were used to assess differences in mortality rates. Results: Patient characteristics for elective and acute procedures were different. Females were generally older (elective: 69 vs. 62 years, p < 0.001, acute: 70 vs. 62 years, p = 0.002), with smaller body surface area (elective/acute: 1.8 vs. 2.1 m2, p < 0.001), lower preoperative haemoglobin (elective: 8.3 vs. 8.9 mmol/L, p < 0.001, acute: 7.8 vs. 8.4 mmol/L, p < 0.001) and estimated glomerular filtration rate (elective: 64 vs. 91 mL/min, p < 0.001; acute: 67 vs. 83 mL/min, p = 0.004). Females undergoing elective procedures had a lower body mass index (25.0 vs. 26.6 kg/m2, p = 0.006), better left ventricle function (p = 0.048) and higher incidence of chronic obstructive pulmonary disease (15 vs. 8%, p = 0.032). In elective procedures, the 20-year mortality rate (49% vs. 30%, p < 0.001) was significantly higher in females, especially those under 60 years (OR of 3.158 [1.2–8.6], p = 0.024). Mortality rates up to one year were comparable. Five-year mortality rate (26% vs. 16%, p = 0.027) was higher. Females had longer ventilation times (32% vs. 15%, p < 0.001) and intensive care unit stays (2 vs. 1 days, p = 0.005). For acute procedures, morbidity and mortality rates were comparable between sexes. Conclusions: Females under 60, undergoing elective ascending aortic surgery showed higher long-term all-cause mortality rates. Implementing sex-specific management strategies and extended follow-up could be essential for improving outcomes in this group.