Background: Oral cavity squamous cell carcinoma (OCSCC) is a major health concern in India, with over 75% of patients presenting with locally advanced disease. Combined modality treatment with surgery followed by adjuvant radiotherapy improves survival outcomes. Timely initiation of radiotherapy, ideally within six weeks of surgery, and a Treatment Package Time (TPT) the total interval from the date of surgery to the completion of radiotherapy under 100 days are considered critical for optimal outcomes. Methods: A prospective cohort study was conducted at Madurai Medical College, Regional Cancer Centre during November 2023 to November 2024 in fifty patients with histologically confirmed OCSCC who underwent surgical resection followed by planned adjuvant radiotherapy. Four patients who did not complete radiotherapy were excluded. Demographic data, tumor characteristics, Surgical type and radiotherapy timing, and TPT were compared and analysed. Results: Among the 46 patients, 65.2% were male, and 91.4% had a history of tobacco use. The most common tumor sites were buccal mucosa (37.0%) and tongue (30.4%). Advanced-stage tumors (T3-T4a) were observed in 71.7% of patients, with nodal involvement in 67.4%. Only 30.4% initiated radiotherapy within six weeks of surgery. TPT was ≤100 days in 52.2% of patients, while 47.8% exceeded this duration. Flap reconstruction was performed in 74.0% of patients; although more patients in this group completed treatment within 100 days, the association was not statistically significant (p = 0.129). Conclusion: A substantial proportion of OCSCC patients experienced delays in adjuvant radiotherapy and prolonged TPT. Efforts to streamline postoperative care and reduce delays are essential to improve treatment outcomes.