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: (I) 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.