<p>Positional plagiocephaly, also known as deformational or non-synostotic plagiocephaly, is a common cranial deformity in infancy resulting from sustained external mechanical forces acting on the developing skull. Its prevalence has increased in recent decades, paralleling widespread adoption of supine sleep positioning recommendations. Although generally considered a benign condition, uncertainty persists regarding optimal management strategies, particularly the role and timing of cranial orthotic therapy. Conservative approaches, including repositioning techniques and physical therapy, are frequently employed, while helmet therapy is typically considered for moderate to severe cases or when initial treatments fail. This systematic review summarizes current evidence on therapeutic interventions for positional plagiocephaly, focusing on cranial shape outcomes, modifiers of treatment response, and safety profiles. The available evidence suggests that helmet therapy appears to be associated with faster early correction of cranial asymmetry, particularly in infants with moderate-to-severe deformity. However, current data do not demonstrate clear long-term superiority over conservative management, as differences between treatment modalities tend to diminish over time. These findings support the interpretation that cranial orthotic therapy may primarily accelerate the rate of correction rather than fundamentally alter long-term cranial morphology. An updated, age- and severity-based diagnostic and management algorithm is proposed to support individualized, evidence-informed clinical decision-making. These findings should be interpreted in the context of the limited number of included studies and the observational nature of the available evidence.</p>