Background The preschool age is a period of both physical and intellectual growth in a child. It is therefore a very important period for detecting preventable and treatable visual problems of childhood which may militate against the attainment of the full potential of the child. Aim The aim of this study was to determine the prevalence and causes of ocular disorders among preschool children in Ijebu North Local Government of Ogun State. Methods This was a community based descriptive, cross-sectional study. A multi-stage random sampling technique was used to select 560 children from a total of 9,944 children within ages 3 to 5 years attending both government and private nursery schools in Ijebu North Local Government Area. All the selected preschool children met the inclusion criteria, their parents or guardians consented to the study and had their demographic and other relevant data collected. They also underwent full ophthalmic assessment including visual acuity assessment with Lea symbol chart, binocular depth perception assessment with Lang stereo test and ocular alignment assessment with Hirschberg test and cover test. Anterior segment was assessed with penlight after which all their pupils were dilated for cycloplegic autorefraction. Posterior segment examination, through dilated pupils, was assessed thereafter using binocular indirect ophthalmoscope.