We aimed to study the prevalence of refractive conditions in Singapore teenagers. Grade 9 and 10 students (n = 946) aged 15–19 years from two secondary schools in Singapore were recruited. The refractive errors of the students’ eyes were measured using non-cycloplegic autorefraction. Sociodemographic data and information on risk factors for myopia (such as reading and writing) were also obtained using an interviewer-administered questionnaire. The prevalence of refractive conditions was found to be: myopia [spherical equivalent (SE) at least −0.50 D] – 73.9%, hyperopia (SE at least +0.50 D) – 1.5%, astigmatism (cylinder at least −0.50 D) – 58.7% and anisometropia (SE difference at least 1.00 D) – 11.2%. After adjusting for age and gender, currently doing more than 20.5 h of reading and writing a week was found to be positively associated with myopia [odds ratio 1.12 (95% CI 1.04–1.20, p = 0.003)], as was reading and writing at a close distance and a better educational stream. The prevalence of myopia (73.9%) in Singapore teenagers is high. Current reading and writing habits, reading at close distances and a better educational stream are possible risk factors for myopia.