Background: Attention-deficit/hyperactivity disorder is the most common neurobehavioral rndisorder and one of the most prevalent chronic health conditions of childhood. rnSymptoms of the disorder affects school performance and disrupt class. So, teachers arernoften the first ones to recognize it. Despite the irreplaceable role of teachers for the diagnosisrnand treatment of ADHD studies done on teachers‟ knowledge and attitude towards ADHDrnare rare. Thus, the aim of this study was to assess primary school teachers‟ knowledge andrnattitude towards ADHD and factors affecting them at selected primary schools in rnAddis Ababa, Ethiopia, 2019 G.C. rnMethods: Institution based cross-sectional study was conducted from March11 to April 19,rn2019 in Addis Ababa, Ethiopia. Simple random sampling technique was used to select 416rnprimary school teachers from 28 schools. Self-administered questionnaire was used to collectrnthe data. And data was entered using Epidata 4.3 and analyzed using SPSS version 25.rnBivariate and multivariate logistic regressions were used for analysis applied at 95% CI.rnResult: Total of 387 questionnaires were replied with a response rate of 93%. Overallrnteachers‟ mean knowledge score was 13.83 ± 6.03. Around 58.7% of study participants hadrnscored above the mean value. The respondents age [AOR=1.06 (1.012, 1.122)], receivingrncourses about ADHD in college [AOR=2.57 (1.485, 4.446)] and receiving informationrnthrough any media about ADHD [AOR=1.71 (1.059, 2.787)] were found to be the importantrnpredictors of scoring above the mean value. Around 56.1% of study participants had scoredrnabove the mean attitude score. Plus only receiving information through a media about ADHDrnwas found to be the important predictor of scoring above the mean attitude scorern[AOR=1.529].rnConclusion: Teachers‟ age, receiving courses about ADHD in college and receivingrninformation through any media about ADHD were the important predictors of scoring abovernthe mean knowledge score. And only receiving information through a media about ADHD wasrnfound to be the important predictor of scoring above the mean attitude score. rnRecommendations: Ministry of Education, school officials and health professionals shouldrnwork to enhance teachers‟ knowledge and attitude by giving courses towards ADHD, preparernin service trainings and raise awareness through media.