Several studies have compared perioperative parameters and early postoperative morphology between endoscope-assisted strip craniectomy with orthotic therapy (endoscopic repair) and cranial vault remodeling (open repair). To extend these results, the authors evaluated school-age anthropometric outcomes after these techniques across three institutions. School-aged children (age range 4-18 years) with previously corrected isolated sagittal craniosynostosis were enrolled. Upon inclusion, 3D photographs and patient-reported outcomes were obtained, and the cephalic index and head circumference z-scores were calculated. Analyses of covariance models controlling for baseline differences and a priori covariates were performed. Eighty-one participants (median [range] age 7 [4-15] years) were included. The mean (95% CI) school-age cephalic index was significantly higher in the endoscopic cohort, though within the normal range for both groups (endoscopic 78% [77%-79%] vs open 76% [74%-77%], p = 0.027). The mean change in the cephalic index from preoperation to school age was significantly greater in the endoscopic group (9% [7%-11%] vs open 3% [1%-5%], p < 0.001). Compared to preoperative measurements, mean school-age head circumference z-scores decreased significantly more in the open cohort (-1.6 [-2.2 to -1.0] vs endoscopic -0.3 [-0.8 to -0.2], p = 0.002). Patient-reported levels of stigma were within the normal limits for both groups. Endoscopic and open repair techniques effectively normalize school-age anthropometric outcomes. However, endoscopic repair produces a clinically meaningful and significantly greater improvement in the school-age cephalic index, with maintenance of head growth. These findings demonstrate the importance of early referral by pediatricians and inform treatment decisions.