Nevirapine, a non-nucleoside reverse transcriptase inhibitor (NNRTI), is widely prescribed in antiretroviral therapy (ART) for HIV treatment. Although effective, it is associated with rare but severe adverse drug reactions, including Stevens-Johnson syndrome (SJS), a life-threatening mucocutaneous disorder. This case report describes a Middle age HIV-positive man who developed SJS following nevirapine initiation, highlighting the importance of timely recognition, management, and the need for clinician vigilance to prevent adverse outcomes in antiretroviral therapy.