Positional plagiocephaly is a craniofacial condition resulting from infant positioning that applies pressure consistently to a part of the skull. This study analyzed the prevalence of, and costs associated with orthotic helmet treatment for positional plagiocephaly and assessed inequities in treatment between medically underserved areas (MUAs) and non-MUAs using health insurance claims data from the Center for Health Information and Analysis (CHIA) in Massachusetts for the years 2016–2021. The mean percentage of patients receiving orthotic helmet therapy was 4.3% (SD=0.49, 95% CI=3.88–4.91, P=0.44). MUAs contained 37.2% of patients with positional plagiocephaly and 2.9% of MUA patients were treated with helmets compared with 5.2% of non-MUA patients (P<0.01). There was a significant decline in the percentage of patients prescribed helmeting therapy over the course of the study (P<0.01). The average copay amount for public insurance was $0.00, and for private insurance, it was $559.8 (SD=160.7, 95% CI=529.1–590.5, P<0.01). Of 3295 claims for orthotic helmet treatment, 92 were fully denied (2.8%). Private insurers issued more fully denied claims (3.8%) than public insurance (1.1%) (P<0.01). We found that public insurance is favorable for patients seeking treatment due to a lower likelihood of full denial and lower copayments. In addition, we found that there is a significant disparity in the prevalence of helmet treatment in MUAs, and the percentage of patients treated with helmeting therapy has declined over time.