Background <p>Kaposi sarcoma (KS) is a rare vascular neoplasm associated with human herpesvirus-8 (HHV-8) infection and is most commonly encountered in immunocompromised individuals. Primary tonsillar involvement in HIV-negative, immunocompetent patients is exceptionally rare, with only a limited number of cases reported in the literature.</p> Aims <p>To present a rare case of primary tonsillar Kaposi sarcoma in an HIV-negative, immunocompetent patient with long-term follow-up, and to review the relevant literature focusing on clinical presentation, diagnostic approach, and management strategies.</p> Methods <p>We report the clinical course of a 36-year-old HIV-negative male who presented with a unilateral tonsillar mass and underwent tonsillectomy. The diagnosis of Kaposi sarcoma was established through histopathological evaluation and confirmed by HHV-8 immunohistochemical staining. Long-term clinical follow-up was performed, and a targeted review of previously published cases of tonsillar KS was conducted.</p> Results <p>Following surgical excision, the patient remained disease-free for 16 years. Subsequently, cutaneous recurrences of Kaposi sarcoma developed and were successfully treated with oral etoposide chemotherapy and localized radiotherapy, resulting in effective disease control without further progression.</p> Conclusions <p>Primary tonsillar Kaposi sarcoma in HIV-negative, immunocompetent patients is an extremely rare clinical entity but should be considered in the differential diagnosis of tonsillar masses. HHV-8 immunostaining is essential for accurate diagnosis. Surgical excision, combined with systemic and local therapies for recurrence, can provide durable disease control. Long-term follow-up is crucial due to the potential for late multifocal recurrence.</p>