Stevens-Johnson syndrome is a medical emergency which is characterized by skin and mucosal reaction to the use of certain drugs. Atypical Steven-Johnson syndrome can occur due to various microorganisms and Mycoplasma pneumoniae being one of them. We present a clinical course, diagnosis, and successful management of Steven-Johnson syndrome-toxic epidermal necrolysis (SJS-TEN) overlap due to Mycoplasma pneumoniae in a 17-year-old Nepalese female. In the resource-limiting country and hospitals where serology and PCR for M. pneumoniae is not easily accessible, a simple bedside cold agglutination test can be done to increase the suspicion of infectious cause (most common M. pneumoniae ) of SJS-TEN overlap. M. pneumoniae infection should be considered in all cases of mucositis, especially in patients having preceding respiratory tract infections (tracheobronchitis).