Background Myopia is the leading cause of correctable visual impairment and preventable blindness worldwide. Genetic and environmental factors contribute to the development of myopia. Myopia is appearing with greater prevalence in young children. Objective This study aimed to assess the prevalence and associated factors of myopia among school children in Bahir Dar city, Northwest Ethiopia, 2019. Methods and materials A school-based cross-sectional study was conducted among school children of 6 to 18 years of age in Bahir Dar city from October to November 2019. A pretested interviewer-administered structured questionnaire was used to collect data among 634 participants using a multi-stage sampling technique from primary and secondary schools. Cycloplegic refraction was performed by optometrists for each student with 1% cyclopentolate eye drop, and subjective refraction was carried out to determine the final prescription of the students. Myopia was defined as spherical equivalent refractive error of [greater than or equal to] 0.5 diopter in either eye. Data were entered into Epi Info version 7 and exported to Statistical Package for Social Sciences version 23 for analysis. Tables, frequency, and mean were used for descriptive statistics. Bivariable and multivariable logistic regression analyses were done to identify risk factors of myopia. Odds ratio with 95% confidence level was determined and variables with p-value of Results Among a total of 601 study participants, 51 (8.49%) were myopic. Age group of 10-13 years (AOR = 6.54: 95% CI = 5.56-10.86), 14-18 years (AOR = 6.32: 95% CI = 5.32-9.69), 2-4 hour per day mobile exposure (AOR = 3.69: 95% CI = 1.63-8.38), 4 hour per day mobile exposure (AOR = 11.6: 95% CI = 4.41-30.42), near working distance of Conclusions The prevalence of myopia was high among school children in Bahir Dar city. Older age, longer duration of mobile exposure, shorter near working distance were the risk factors for the development of myopia whereas having outdoor activity was the protective factor.