The objective of this study was to determine the prevalence of distant visual acuity defect among high school girls of Al-Khobar City. A sample of 966 students was selected randomly for the study. Distant visual acuity for each eye was measured with use of Snellen's E chart. Visual acuity of 6/9 or more without aid [glasses/contact lenses] was considered as normal or near normal. Vision defects were arbitrarily classifdied into mild [> 6/9 - ≤ 6/15], moderate [> 6/15 - < 6/60] and severe [≤ 6/60]. The prevalence of unaided defective vision [6/9] was 24.9% for both eyes and 32.8% when one or both eyes were considered. Of the 966 students, 237 [24.5%] had a visual acuity of less than 6/9 with 105 [10.9%] of these having a moderate visual defect [> 6/15 - < 6/60] and 42 [4.3%] a severe visual defect [≤ 6/60]. Of the 966 students examined 340 [35.2%] had never had an eye check-up in the past. Based on these results there is a need to initiate periodic visual screening programs for children from the early age of school entry [6 years] in Saudi Arabia and every two to three years thereafter.