Background: Normalized growth curves are an essential component in management of pediatric patients. Benign enlargement of subarachnoid spaces (BESS) is a common condition in infants that results in deviation from expected head growth but does not have long term implications. Differentiating BESS from pathological conditions is critical to minimize unnecessary imaging and specialist evaluations. Standardized growth charts specific to BESS do not exist, complicating monitoring and management. Methods: An analysis of head circumference (HC) data was performed for 315 children aged 0-6 years diagnosed with BESS at CHEO. Growth charts were created using Generalized Additive Models for Location, Scale, and Shape (GAMLSS). Z-scores derived from HC measurements were compared to World Health Organization (WHO) norms, stratified by sex. Results: Benign macrocephalic patients consistently tracked above the 97th percentile of WHO curves, with the 50th percentile in this cohort aligning with the 97th percentile of WHO data. HC growth accelerated in early infancy, stabilizing around ages 2-3. Growth charts demonstrated distinct patterns for BESS compared to normative data. Conclusions: This study provides novel charts for BESS, enabling improved monitoring and clinical management. These charts have the potential to reduce unnecessary imaging and specialist referrals, alleviating anxiety for caregivers and clinicians while optimizing resource use.