Objectives: To determine the patient and treatment characteristics associated with delay in post-operative radiation therapy (PORT) for patients treated surgically for head and neck squamous cell cancer (HNSCC) at our institution. Design: Single institution retrospective review Setting: Tertiary care academic medical center Participants: Patients treated surgically for HNSCC that underwent PORT between 2013-2016 Main outcomes measures: Time from surgery to initiation of PORT. Results: 140 patients met inclusion criteria. A majority did not start radiotherapy within six weeks. Factors associated with a delayed initiation of PORT included length of stay >8 days, 30-day readmission, no adjuvant chemotherapy, post-operative complications, and fragmented care. Conclusion: A majority of patients did not initiate PORT within the guideline-recommended 6 weeks. Modifiable risks factors that delay initiation of PORT were identified.