<p>The oral viral microbiome (or virome), encompassing a diverse community of viruses within the oral cavity, has emerged as a significant yet underexplored factor in head and neck cancers (HNCs). This review synthesizes recent evidence linking the oral virome to head and neck carcinogenesis, particularly oropharyngeal and nasopharyngeal carcinomas—the most common virus-associated subtypes of HNCs. Beyond pathogenesis, the diagnostic and therapeutic implications of the oral virome are explored, including non-invasive salivary detection of viral biomarkers for early cancer diagnosis, the development of targeted antiviral therapies, and preventive vaccination strategies—exemplified by the success of HPV vaccines in reducing the incidence of oropharyngeal cancers. Despite these advancements, challenges persist, including technical limitations, the need for longitudinal studies, and the integration of multi-omics approaches. A comprehensive understanding of the oral virome could revolutionize cancer diagnostics, therapeutics, and prevention. Moving forward, collaborative interdisciplinary efforts will be essential to fully leverage virome research for improving HNC outcomes.</p>