Children with neurofibromatosis type 1 have an increased incidence of optic pathway gliomas and central precocious puberty. This study explores whether the presence and location of optic pathway gliomas is associated with the changes in height and pubertal onset that are seen in these children. Retrospective analysis was undertaken of 75 individuals with a diagnosis of both neurofibromatosis type 1 and optic pathway gliomas, known to a single quaternary neurofibromatosis type 1 center, over a 20-year period. Central precocious puberty was more likely with optic pathway gliomas, observed in 28% of the cohort, and was associated with either optic chiasm involvement (P = .046) or bilateral optic pathway gliomas (P < .001). This is presumably due to disruption in the hypothalamic-pituitary axis. Height standard deviation scores were not significantly different from the general population. Increased clinical monitoring of pubertal status is consequently required for children with neurofibromatosis type 1 and an optic pathway glioma.