Context: Deformational plagiocephaly (DP) is on the rise in pediatric patients. The current standard of care recommended for management is repositioning with possible addition of cranial orthoses. However, strong data are lacking to support these recommendations. Osteopathic manipulative treatment (OMT) is another treatment option for DP that is also lacking evidential support. Objectives: This retrospective chart review study investigated the effects of OMT at restoring a more symmetrical cranial bone configuration in children with DP. Methods: A retrospective chart review was performed on medical records of patients with a diagnosis of DP from three private practices over a 4-year period from September 2017 to December 2021. Inclusion criteria were diagnoses of DP by a referring physician and aged 10 months or less at the time of initial evaluation and treatment. Patients were excluded if they had confounding diagnoses such as genetic syndromes or severe torticollis. A total of 26 patients met these criteria, and their records were reviewed. The main outcome reviewed was anthropometric assessment of the cranium, mainly the cranial vault asymmetry index (CVAI). Results: Participants demonstrated a mean CVAI - a measure that determines the severity of DP - of 6.809 (±3.335) (Grade 3 severity) at baseline, in contrast to 3.834 (±2.842) (Grade 2 severity) after a series of OMT treatments. CVAI assessment after OMT reveals statistically significant (p≤0.001) decreases in measurements of skull asymmetry and occipital flattening. No adverse events were reported throughout the study period. Conclusions: The application of OMT has shown potential benefit for reducing cranial deformity in patients with DP. Keywords: cranial anthropometric measurements; cranial dysmorphology; flat head; osteopathic cranial manipulative medicine (OMM); osteopathic manipulative treatment (OMT); plagiocephaly.