Objectives: To develop and validate a classification of sleeve gastrectomy leaks able to reliably predict outcomes, from protocolized computed tomography (CT) findings and readily available variables. Summary of Background Data: Leaks post sleeve gastrectomy remain morbid and resource-consuming. Incidence, treatments, and outcomes are variable, representing heterogeneity of the problem. A predictive tool available at presentation would aid management and predict outcomes. Methods: From a prospective database (2009-2018) we reviewed patients with staple line leaks. A Delphi process was undertaken on candidate variables (80-20). Correlations were performed to stratify 4 groupings based on outcomes (salvage resection, length of stay, and complications) and predictor variables. Training and validation cohorts were established by block randomization. Results: A 4-tiered classification was developed based on CT appearance and duration postsurgery. Interobserver agreement was high (k ¼ 0.85, P < 0.001). There were 59 patients, (training: 30, validation: 29). Age 42.5 AE 10.8 versus 38.9 AE 10.0 years (P ¼ 0.187); female 65.5% versus 80.0% (P ¼ 0.211), weight 127.4 AE 31.3 versus 141.0 AE 47.9 kg, (P ¼ 0.203). In the training group, there was a trend toward longer hospital stays as grading increased (I ¼ 10.5 d; II ¼ 24 d; III ¼ 66.5 d; IV ¼ 72 d; P ¼ 0.005). Risk of salvage resection increased (risk ratio grade 4 ¼ 9; P ¼ 0.043) as did complication severity (P ¼ 0.027).Findings were reproduced in the validation group: risk of salvage resection (P ¼ 0.007), hospital stay (P ¼ 0.001), complications (P ¼ 0.016). Conclusion:We have developed and validated a classification system, based on protocolized CT imaging that predicts a step-wise increased risk of salvage resection, complication severity, and increased hospital stay. The system should aid patient management and facilitate comparisons of outcomes and efficacy of interventions.