Purpose This study evaluates serial radiographic changes in the maxillary sinus of patients with oral cancer after an inferior maxillectomy and a soft tissue free flap reconstruction. Methods Fifty‐six patients were evaluated between Oct 2005 and Mar 2017 from an institutional database. Preoperative and surveillance imaging was reviewed at set time‐points. Maxillary sinus scores were allotted based on a modification of the Lund–MacKay staging system. Patients were evaluated for change in sinus score. A univariate (UV) and multivariate (MV) analysis was performed. Results There were 53.5% T3/T4 category tumors and 68% received adjuvant treatment. Median follow‐up was 24.4 months. Preoperative mean sinus score was 0.27 ± 0.44 and postoperative mean sinus score at 24 months was 1.2 ± 1.3 (p = <0.001). On UV analysis advanced T‐stage at 12 months (OR 6.7, 95% CI 1.2–50.3, p = 0.01) and 24 months (OR 5.2, 95% CI 1.03–36.8, p = 0.04) was associated with significantly higher sinus score. On MV analysis, advanced T‐stage continued to be associated with increased odds for higher sinus score (OR 4.9, 95% CI 1.1–26.8, p = 0.039). Conclusion A mild increase in postoperative sinus score is seen in this cohort of patients. Advanced T‐stage is associated with increased odds for higher sinus scores.