Background: Meningioma is the most common primary intracranial tumor in adults, and survival outcomes are influenced by histopathological grade, tumor characteristics, and treatment strategies. This study aimed to evaluate overall survival (OS) and identify prognostic factors in patients with meningioma treated at a national referral cancer center in Indonesia. Methods: A retrospective cohort study was conducted at Dharmais National Cancer Center Hospital, including adult patients with histopathologically confirmed intracranial meningioma who underwent surgical resection between January 2019 and 17 August 2025. Overall survival was calculated from the date of histopathological diagnosis to death or last follow-up and analyzed using Kaplan–Meier methods and Cox proportional hazards regression. Results: A total of 114 patients were included (mean age 48.1 ± 10.5 years; 86.8% female), with most tumors classified as WHO Grade I (64.0%) and located at the skull base (57.0%). Subtotal resection was more common (67.5%), and 71.9% did not receive adjuvant radiotherapy. During follow-up, 14.0% of patients died, with cumulative overall survival rates of 95.6% at 6 months and 86.0% at 96 months. On multivariate analysis, only WHO tumor grade remained an independent prognostic factor (HR 2.199; 95% CI 1.161–4.167; p = 0.016), with higher grades associated with worse survival. Extent of resection and adjuvant radiotherapy were not significantly associated with overall survival after adjustment. Conclusions: In this Indonesian tertiary referral cohort, WHO tumor grade emerged as the only independent predictor of overall survival, underscoring its important prognostic role in meningioma; however, these findings should be interpreted with caution due to incomplete clinical data and relatively short follow-up duration. The high proportion of complex cases, including skull base tumors, reflects referral patterns and may also influence treatment outcomes.