Objective. To perform early detection of visual impairment in schoolchildren and to investigate its association with academic performance. MethOds. Cross-sectional study using a sample of third-grade students from public elementary schools of the municipality of Juiz de Fora, state of Minas Gerais, Brazil. Students performed the visual acuity (VA) test using the Snellen chart. We also analyzed school records and administered a previously validated self-administered questionnaire. We considered that there was low VA when the VA value achieved using the chart was lower than or equal to 0.7, while poor academic performance was identified when the average grades of the last school year did not reach 60 points. Results. We analyzed 222 students from five public schools. In terms of visual acuity, 31% of the students had impaired VA in the right eye and 29.8% of the students had impaired VA in the left eye. Our sample had 15.5% of students with fair or poor academic performance. Among the students with normal VA, 89.5% had satisfactory academic performance, while among those with impaired VA, only 75% achieved satisfactory performance (p = 0.015). cOnclusiOn. The present study suggests that there is an association between low VA and poor academic performance in the sample assessed.