Introduction: Delays in commencing post-operative radiation therapy (PORT) and prolongation of overall treatment times (OTT) are associated with reduced overall survival and higher recurrence rates in patients with head and neck squamous cell carcinoma (HNSCC). The objective of this study was to evaluate treatment delays, factors contributing to those delays and to explore strategies to mitigate them. Methods: This retrospective study included patients with mucosal HNSCC at Townsville University Hospital treated with curative intent surgery and PORT between June 2011 and June 2019. The proportion of patients who experienced delays in commencing PORT (>6 weeks) and OTT were evaluated and reasons for these delays were explored.Results: The study included 94 patients of which 70% experienced PORT delay. Surgery at an external facility (81% vs 56%, P = 0.006) and longer postoperative length of stay (P = 0.011) were significantly associated with a higher incidence of PORT delay. Aboriginal and Torres Strait Islander patients had a higher rate of PORT delay (89% vs 68.2%, P = 0.198). Significant delays were noted from time of surgery to radiation oncology (RO) consult and from RO consult to commencement of radiation treatment. Conclusion: This study demonstrates that the prevalence of PORT delay for patients with HNSCC remains high with room for improvement. Potential strategies to improve delays include developing effective care coordination, addressing specific needs of Indigenous patients, implementing reliable automated tracking and communication systems between teams and harnessing existing electronic referral systems.