Background: Optic pathway gliomas associated with neurofibromatosis type 1 (NF1-OPGs) may adversely affect visual acuity, but data regarding visual field (VF) outcomes after treatment in children are limited. The purpose of this study was to investigate the effects of NF1-OPGs on VF function in a large cohort of children after treatment with chemotherapy. Methods: We performed a retrospective, international, multicenter study of VF outcomes in patients treated with chemotherapy for NF1-OPGs. Results: A total of 25 participants underwent VF testing using formal perimetric techniques. At the end of treatment, 19 participants (76%) had persistent VF deficits. Formal VF testing was available for 16 participants (64%) at initiation and completion of treatment. Of the 16 children who underwent VF testing at initiation and completion of treatment, 7 (44%) showed stability of VF changes, 3 (19%) showed improvement of VF function, and 6 (38%) had worsening of VFs. Improvement or worsening of VF outcome did not always correlate with visual acuity outcome. Posterior tumor location involving the optic tracts and radiations was associated with more frequent and more profound VF defects. Conclusions: In our study cohort, children undergoing initial chemotherapy for NF1-OPGs had a high prevalence of VF loss, which could be independent of visual acuity loss. A larger, prospective study is necessary to fully determine the prevalence of VF loss and the effects of chemotherapy on VF outcomes in children with NF1-OPGs.