BACKGROUND Multiple myeloma is mainly a disease of the elderly. The diagnosis of multiple myeloma in patients under 30 years of age is rare. A rare case is presented of a 17-year-old girl diagnosed with multiple myeloma who was successfully treated with autologous hematopoietic stem cell transplantation (ASCT). CASE REPORT A 17-year-old Vietnamese girl presented with pain in the left hip and difficulty walking. She was diagnosed with stage IIIA IgG lambda (l) multiple myeloma and was treated with a bortezomib-based chemotherapy regimen followed by ASCT. The patient showed a good response to treatment. At 14-month follow-up, her bone pain had resolved, and her ability to walk was improved. CONCLUSIONS A rare case of multiple myeloma is presented in a 17-year-old girl who responded well to ASCT.