<p>Oral Squamous Cell Carcinomas treatment often results in significant functional impairments in speech, swallowing, and mastication, influenced by tumor site and treatment modality. This study aimed to evaluate the longitudinal impact of these factors on functional Quality Of Life in oral cancer survivors. A prospective study enrolled 56 patients with Oral Squamous Cell Carcinomas. Functional impairments were assessed using a validated head and neck cancer- specific Quality Of Life questionnaire at four time points: baseline, 2 weeks, 1 month, and 6 months post-treatment. Repeated-measures analysis of variance and regression analysis were used to evaluate correlations between tumor site, treatment modality, Reconstructive Surgical Procedures, and functional outcomes in speech, swallowing, and mastication. Tumors of the tongue and floor of mouth were associated with significantly greater impairments in speech and swallowing (<i>p</i> &lt; 0.05). Patients undergoing free flap Reconstructive Surgical Procedures and multimodal therapy (surgery combined with radiotherapy and/or chemotherapy) exhibited more severe long-term functional deficits compared to those with primary closure or surgery alone. Longitudinal analysis showed progressive improvement over 6 months, though functional scores remained lower in the tongue cancer subgroup. Tumor site and treatment modality significantly influence post-treatment functional Quality Of Life in oral cancer survivors. These findings highlight the need for prehabilitation and site-specific rehabilitation strategies to enhance long-term survivorship outcomes.</p>