Orbital dermoid cysts are benign choristomas that arise from the entrapment of ectodermal elements adjacent to the fetal bony suture lines. They are considered congenital, but not all are diagnosed at birth. They are the most common orbital tumors in children. While superficial dermoid cysts appear early in life, deep dermoid cysts remain clinically occult until adolescence or adulthood, when they enlarge and may cause proptosis, ocular and orbital symptoms, and even neurological symptoms. In addition, many deep orbital dermoid cysts present with chronic inflammation resulting from lipid leakage from the cysts. They pose a diagnostic and therapeutic challenge, require radiological imaging for planning the surgical approach and may be difficult to remove. Early diagnosis and complete surgical removal of the cysts are the recommended therapeutic approach. In this paper, we present a literature review of deep orbital dermoid cysts to provide useful guidance for their diagnosis and management.