Purpose To evaluate the longitudinal reproducibility of optical coherence tomography (OCT) measurements in normal and glaucomatous eyes of children. Methods In this 2-setting prospective study, OCT-3 was used to obtain fast retinal nerve fiber layer (RNFL) and macular thickness scans. In the first study setting, the normal eyes of healthy children were scanned on presentation, at 2 weeks, and 3 years, with axial length measured at the first and last examinations. In the second setting, OCT scans of patients in the pediatric glaucoma clinic were performed over 4 years as clinically indicated. Eyes were classified as “normal” (normal eyes and those with physiologic cupping but normal intraocular pressure [IOP]); “mild glaucoma” (increased IOP and a normal optic nerve appearance); or “advanced glaucoma” (severe cupping or progressive glaucoma). Intraclass correlation coefficients were used to evaluate the reproducibility of measurements on the same day and over time. Results In the first setting, 8 normal eyes were included. Axial length increased 0.11 ± 0.04 mm/year over an average of 3.3 years (P = 0.03); there was no statistically significant change in RNFL thickness (P = 0.30). In our second setting, 27 normal eyes and 37 eyes with glaucoma were included. Intraclass correlation coefficients across the 3 visits for total macular volume were 0.80-0.91 and for average RNFL were 0.73-0.95. Conclusions Global OCT measurements in children were reproducible over years and were not affected by normal increase in axial length. OCT shows promise as an objective tool for longitudinal assessment of children.