Juvenile generalized pustular psoriasis (GPP) is rare and often resistant to conventional systemic therapy such as methotrexate, retinoic acid and cyclosporin A. GPP can be induced by deficiency of interleukin (IL)-36 receptor antagonist (DITRA). No standardized guidelines are available for juvenile GPP or DITRA, and a uniformly safe and effective biologic agent has not been identified. However, multiple biologics approved for use in plaque-type psoriasis have also been used in GPP. Herein, we report a case of a 6-year-old Taiwanese boy with GPP and homozygous mutation at c.115+6T>C within the IL-36 receptor antagonist (IL36RN) gene, who was treated successfully with secukinumab after failure of prior methotrexate, acitretin, cyclosporin A, etanercept and adalimumab. Similar to two previously reported non-adult cases of GPP successfully treated with secukinumab, our case also demonstrated a history of repeated treatment failures with several conventional oral systemic agents and biologics. Different from these two cases, however, ours is the first of juvenile GPP successfully treated with secukinumab monotherapy, without using other systemic agent concurrently during the use of secukinumab.