Background: This study aimed to describe the treatment strategies and outcomes for women with newly diagnosed advanced high-grade serous or endometrioid ovarian cancer (OC). Methods: This observational study collected real-world medical record data from eight Western countries on the diagnostic workup, clinical outcomes, and treatment of adult women with newly diagnosed advanced (Stage III–IV) high-grade serous or endometrioid OC. Patients were selected backward in time from April 1, 2018 (the index date), with a target of 120 patients set per country, followed for ≥20 months. Results: Of the 1119 women included, 66.9% had Stage III disease, 11.7% had a deleterious BRCA mutation, and 26.6% received bevacizumab; 40.8% and 39.3% underwent primary debulking surgery (PDS) and interval debulking surgery (IDS), respectively. Of the patients who underwent PDS, 55.5% had no visible residual disease (VRD); 63.9% of the IDS patients had no VRD. According to physician-assessed responses (at the first assessment after diagnosis and treatment), 53.2% of the total population had a complete response and 25.7% had a partial response to first-line chemotherapy after surgery. After ≥20 months of follow-up, 32.9% of the patients were disease-free, 46.4% had progressive disease, and 20.6% had died. Bevacizumab use had a significant positive effect on overall survival (hazard ratio [HR], 0.62; 95% CI, 0.42–0.91; p =.01). A deleterious BRCA status had a significant positive effect on progression-free survival (HR, 0.60; 95% CI, 0.41–0.84; p <.01). Conclusions: Women with advanced high-grade serous or endometrioid OC have a poor prognosis. Bevacizumab use and a deleterious BRCA status were found to improve survival in this real-world population. Lay summary: Patients with advanced (Stage III or IV) ovarian cancer (OC) have a poor prognosis. The standard treatment options of surgery and chemotherapy extend life beyond diagnosis for 5 years or more in only approximately 45% of patients. This study was aimed at describing the standard of care in eight Western countries and estimating how many patients who are diagnosed with high-grade serous or endometrioid OC could potentially be eligible for first-line poly(adenosine diphosphate ribose) polymerase inhibitor (PARPi) maintenance therapy. The results highlight the poor prognosis for these patients and suggest that a significant proportion (79%) would potentially be eligible for first-line PARPi maintenance treatment.