A custom-made helmet-like device intended to be worn on the head of an infant with an abnormal head shape (e.g., due to plagiocephaly, brachycephaly, scaphocephaly), or after craniosynostosis repair surgery, to apply pressure to the cranium and improve cranial symmetry/shape during growth over a period of months. It is made of durable materials (e.g., plastic, solid foam) and is designed with patient-specific characteristics (e.g., size, shape) based on head measurements (e.g., clinical pictures, 3-D scans, casts). It is typically worn during daily activities and sleep. This is a single-patient device that can be reapplied during the treatment period (reusable) before being discarded.