Cystic bone lesions encompass a diverse spectrum of benign and malignant conditions, each with distinct clinical, radiological, and pathological features. This chapter systematically reviews key entities, including simple bone cysts, aneurysmal bone cysts, intraosseous lipomas, fibrous dysplasia, hydatid disease, Gorham-Stout disease, and skeletal angiomatosis. This chapter highlights site-specific patterns and age-related prevalence. Radiography and advanced imaging modalities are detailed for lesion characterisation, staging, and follow-up. Management strategies range from observation to curettage/bone grafting and systemic therapy. Complications, including pathologic fractures and malignant transformation, are addressed. This comprehensive guide equips clinicians and radiologists with a structured approach to diagnosis, differential evaluation, and evidence-based management of cystic bone lesions, emphasising multidisciplinary collaboration for optimal outcomes.