Osteocutaneous fibula free flaps (FFFs) are a fundamental component of reconstructive surgery in the head and neck region, particularly after traumatic injuries or oncologic resections. Despite their utility, FFFs are associated with various postoperative complications, such as infection, flap failure, and donor site morbidity, impacting up to 54% of cases. This study aimed to investigate the influence of socioeconomic variables, with a particular focus on median household income (MHI), on the incidence of postoperative complications in FFF reconstruction for head and neck cancer. A retrospective analysis of 80 patients who underwent FFF reconstruction for head and neck cancer at a single center from 2016 to 2022 was conducted. Demographic and patient characteristics, including race, MHI, insurance type, history of radiation therapy, and TNM (tumor, node, metastasis) cancer stage, were evaluated. Logistic regression, controlling for comorbidities, was used to assess the impact of MHI on 30-, 90-, and 180-day postoperative complications. The patient population was predominantly male (n = 51, 63.8%) and White (n = 63, 78.8%), with the majority falling within the $55,000 to $100,000 range of MHI (n = 51, 63.8%). Nearly half of the patients had received neoadjuvant radiation treatment (n = 39, 48.75%), and 36.25% (n = 29) presented with osteoradionecrosis. Logistic regression analysis revealed that the $55,000-$100,000 MHI group had significantly lower odds of developing complications in the 0- to 30-day postoperative period when compared with those in the <$55,000 group (odds ratio [OR], 0.440; 95% confidence interval [CI], 0.205-0.943; P = 0.035). This trend persisted in the 31- to 90-day period (OR, 0.136; 95% CI, 0.050-0.368; P < 0.001) and was also observed in the likelihood of flap takeback. In addition, the $100,000-$150,000 group had significantly lower odds of developing complications in the 31- to 90-day period (OR, 0.182; 95% CI, 0.035-0.940; P = 0.042). No significant difference was found in the >$150,000 group. Median household income is a significant determinant and potentially a more influential factor than neoadjuvant radiation in predicting postoperative complications after FFF reconstruction. Disparities in postoperative outcomes based on income highlight the need for substantial health care policy shifts and the development of targeted support strategies for patients with lower MHI.