Aims Indigenous Australians experience worse head and neck cancer outcomes, yet determinants of treatment delivery remain unclear. This study evaluated attrition from curative treatment recommendation to completion – including acceptance, completion, interruptions and causes – among Indigenous patients discussed at a regional head and neck multidisciplinary team (HNMDT). Methodology A retrospective cohort study of Indigenous patients with first primary mucosal head and neck cancer discussed at a regional HNMDT from 2010–2024 was performed. Clinical records were reviewed to quantify treatment acceptance, completion, interruptions and causes of disruption. Completion was defined as finishing the MDT-prescribed regimen; interruption as ≥1 unscheduled break. Results Among 135 patients, advanced disease predominated (IVA–IVB 67%, IVC 12%), with 91 (67%) recommended curative therapy. Of curative candidates, 81 (89%) accepted treatment. Curative therapy was completed in 65% (59/91) overall, or 73% among those commencing treatment. Completion declined with increasing regimen intensity (p<0.001), from 100% for single-modality therapy to 20% for induction chemotherapy followed by chemoradiotherapy. Among patients commencing radiotherapy locally (n=65), 34% had interruptions. Barriers varied across the pathway: treatment decline was linked to cultural obligations and treatment concerns; systemic therapy non-completion was toxicity-driven; radiotherapy non-completion and interruption reflected toxicity, cultural obligations, family responsibilities, and logistical constraints. Conclusion A substantial gap exists between treatment intent and delivery in Indigenous head and neck cancer care. This reflects late presentation requiring intensive regimens, compounded by toxicity, cultural obligations, family commitments and logistical constraints. Improving outcomes will require culturally responsive models enabling earlier diagnosis and sustained engagement through complex treatment.