Osteopetrosis is a clinical syndrome characterized by the failure of osteoclasts to resorb bone. Excessive bone density can interfere with vital tissues and structures, causing serious problems of the body. Hematopoietic insufficiency, disturbed tooth eruption, nerve entrapment syndromes, and growth impairment may develop in a patient with osteopetrosis. Herein, we present an adolescent girl diagnosed with non-infantile type of osteopetrosis with rare complications of the disease like mandibular osteomyelitis and portal hypertension (PHT) without liver cirrhosis. To our knowledge, this is the first pediatric case with osteopetrosis related PHT.