Purpose <p>Oral squamous cell carcinoma (OSCC) is a significant global health burden, with increasing evidence implicating high-risk viral infections such as human papillomavirus (HPV) and Epstein–Barr virus (EBV) in its pathogenesis. Immunohistochemical (IHC) profiling using viral surrogate markers offers valuable diagnostic and prognostic insights. This study aimed to evaluate the expression of p16, HPV E6, and EBV LMP1 (latent membrane protein) in OSCC tissues using IHC and to explore their associations with clinicopathological parameters, risk factors, recurrence, and survival outcomes, with a particular focus on co-viral infections.</p> Methods <p>A prospective observational study was conducted between April 2021 and March 2024, including 181 histopathologically confirmed OSCC cases. Fresh tumor tissues were subjected to IHC staining for p16, HPV E6, and EBV LMP1. Marker expression was semi-quantitatively scored, and associations with demographic, clinical, and pathological parameters were analyzed statistically.</p> Results <p>Although not statistically significant, p16 expression was more frequently observed in well-differentiated and early-stage OSCC, and in patients with combined alcohol and tobacco use. HPV E6 positivity was more common in tumors of the tongue and floor of the mouth and tended to be lower in tobacco users. EBV LMP1 expression was significantly associated with non-recurrence (<i>p</i> = 0.040), while trends with advanced stage and lymph node involvement were observed but not statistically significant. Co-infection with HPV and EBV was detected in12.3% (20/162) of cases, with no significant association to recurrence or survival.</p> Conclusion <p>IHC detection of p16, HPV E6, and EBV LMP1 provides valuable diagnostic and prognostic information in OSCC. EBV LMP1 may be inversely associated with recurrence, highlighting its potential as a biomarker.</p>