Objective Complications of oral cavity cancer (OCC) surgery have an impact on the quality of life. Therefore, evaluating hospital performance on complication rates can help identify best practices for improving the quality of OCC care. As patient and tumor characteristics also impact hospital results, case‐mix adjustment should be considered to provide a valid hospital comparison. This study investigated hospital variation in the quality indicator “a complicated postoperative course” after OCC surgery. Methods This population‐based cohort included all first primary OCC patients diagnosed between 2018 and 2021 who were surgically treated with curative intent. A complicated postoperative course was defined as 30‐day mortality, unplanned readmission, surgical complications requiring reintervention or prolonged hospital stay, or fistula formation. Hospital performance was analyzed using funnel plots with case‐mix correction. Results A total of 2,266 OCC patients could be included. The distribution of case‐mix variables varied significantly between hospital populations. Nationally, a complicated postoperative course occurred in 13.9% and uncorrected hospital rates ranged from 2.7% to 31.1%. A WHO performance score ≥2, cT3‐T4 tumors, and floor‐of‐mouth tumors were associated with an increased risk of a complicated postoperative course, and non‐squamous cell carcinoma with a decreased risk. Significant outliers remained after case‐mix correction for patient, tumor, and treatment characteristics. Conclusion Complications after OCC surgery are prevalent, especially regarding extensive tumors and surgery. To identify best practices in OCC surgery, hospital performance on a complicated postoperative course should be adjusted for case‐mix and treatment variables. Providing feedback on hospital performance for complications can instigate improvement plans for better outcomes. Level of Evidence 3 Laryngoscope , 135:2411–2419, 2025