Background: Despite recent advances in targeted therapy and immunotherapy for advanced non–small cell lung cancer (NSCLC), carboplatin/pemetrexed/bevacizumab remains a commonly used first-line regimen. However, it is unknown whether the addition of bevacizumab to carboplatin/pemetrexed improves overall survival (OS). Materials and Methods: Using nationally representative curated electronic health record data from Flatiron Health, we performed a retrospective cohort study of patients diagnosed with advanced nonsquamous NSCLC who received ≥1 cycle of carboplatin/pemetrexed ± bevacizumab as initial systemic therapy for stage IV or metastatic/recurrent disease. The OS impact of adding bevacizumab to carboplatin/pemetrexed was assessed using a Cox proportional hazards model to adjust for age, sex, race, original tumor stage, time between diagnosis of metastatic disease and start of chemotherapy, and performance status. In a secondary analysis of patients at a single academic institution, we also adjusted for the presence of brain metastases, hemoptysis, and anticoagulation. Results: A total of 4,724 patients were included, of which 2,759 patients (58%) received carboplatin/pemetrexed and 1,965 (42%) received carboplatin/pemetrexed/bevacizumab. Median OS was 12.1 months (95% CI, 11.2–12.9 months) in the carboplatin/pemetrexed/bevacizumab group compared with 8.6 months (95% CI, 8.1–9.1 months) in the carboplatin/pemetrexed group (P<.001). Bevacizumab use remained associated with improved OS in a multivariate model (hazard ratio, 0.80; 95% CI, 0.75–0.86; P<.001). In the secondary, institutional analysis (N=539), the effect of bevacizumab was unchanged (hazard ratio, 0.75; 95% CI, 0.59–0.96; P=.02). Conclusions: In this large, real-world dataset, the addition of bevacizumab to first-line carboplatin/pemetrexed for metastatic nonsquamous NSCLC was associated with improved OS.