PURPOSE: The purpose of this study was to determine the magnitude and determinants of refractive error (RE) and related ocular morbidities among preparatory and secondary Saudi students in Riyadh. METHODS: This study was conducted in 2017–2018 at preparatory (12–14 years) and secondary (15–18 years) schools. A “Spot Screener” was used to determine if the child passed or failed a refraction test. Fail test meant RE ≥ ± 0.50 D. Data were collected on refractive status in each eye, anisometropia, and strabismus. The type of RE was estimated and analysis was performed for an association to gender, age, and education levels. The use of spectacle while screening defined the compliance of spectacle wear. RESULTS: The study sample was comprised of 708 Saudi students. There were 59.5% of boys. The prevalence of RE was 43.6% (95% confidence interval [CI]: 40.0, 47.3). The prevalence of RE in preparatory and secondary students was 44.5% and 43.2%, respectively. The proportion of myopia (≥ −0.5 D) and hyperopia (≥ +0.5 D) among students with RE was 82.2% and 17.8%, respectively. Family history of RE was positively associated to RE in students (odds ratio: 1.8 [95% CI: 1.3, 2.5]). The current screening initiative identified 45 (6.4%) new cases of RE who required spectacles. The compliance rate for using visual aid among students with RE was 74.6%. The prevalence of anisometropia and strabismus was 3.0% and 4.1%, respectively. CONCLUSIONS: A high proportion of Saudi adolescence in Riyadh have RE. Periodic ophthalmic assessment and refractive services are recommended as part of school health screening initiatives.