Objective. To compare outcomes following osteocutaneous radial forearm and fibula free flap reconstruction of lateral mandibular defects.Study Design. Retrospective case-controlled study.Setting. Historical cohort study.Subjects and Methods. All patients who underwent free flap reconstruction of lateral mandibular defects from 1999 to 2010 were included in this study. Patients were classified into 2 groups based on type of reconstruction: (1) osteocutaneous radial forearm (n = 73) and (2) fibula free flap reconstruction (n = 51). Patient characteristics, length of hospital stay, recipient and donor site complications, and long-term outcomes including postoperative diet were evaluated.Results. Most patients were male (68%) and presented with advanced T-stage (71%) squamous cell carcinoma (94%) involving the alveolus (21%), retromolar trigone (23%), or oral tongue (21%). Median length of hospital stay was 8 days (range, 4-22 days). The recipient site complication rate approached 27% and included infection (n = 11), mandibular malunion (n = 9), exposed bone or mandibular plates (n = 9), and flap failure (n = 5). Most patients demonstrated little to no trismus following reconstruction (94%) and were able to resume a regular or edentulous diet (73%). No difference in complication rates or postoperative outcomes was seen between osteocutaneous radial forearm and fibula free flap groups (P >.05). One patient underwent dental implantation following osteocutaneous radial forearm free flap reconstruction. No patients from the fibula free flap group underwent dental implantation.Conclusion. The osteocutaneous radial forearm and fibula free flap provide equivalent wound healing and functional outcomes in patients undergoing lateral mandibular defect reconstruction. © American Academy of Otolaryngology-Head and Neck Surgery Foundation 2012.