Purpose: The aim of this study was to identify the effects of a newly developed instructional coaching program regarding Attention Deficit HyperactivityDisorder (ADHD) for teachers. Methods: Seventy teachers participated in this study involving a nonequivalent control group and apretest-posttest design. The instructional coaching program consisted of eight 60-minute sessions. The program was developed through a theoreticaldevelopment program involving six steps. To evaluate the effects of the program, data were collected through self-report questionnairesincluding the Knowledge Scale of Attention Deficit Disorder, Attitude Scale of Primary School Teachers Experiencing Students with ADHD, PracticeScale of Educational Intervention Activity, and the Korean ADHD Rating Scale. Data were analyzed with an independent t test, a chi-squaretest, and an ANCOVA using SPSS WIN version 20. Results: The intervention program consisted of 3 sectors, 8 subjects, and 24 content items. Theexperimental group showed a significant improvement in attitudes toward ADHD (F=22.83, pqqqlt;.001). In addition, teacher’s knowledge regardingADHD (F=7.16, p=.010) and the implementation of instructional interventions (F=4.29, p=.043) improved. Further, teachers reported a reductionin children’s ADHD-related behavior (F=4.34, p=.041). Results showed that the coaching program made a positive contribution to teaching skillsand understanding of school-age children with ADHD. Conclusion: The instructional coaching program was well structured and significantly improvednot only teachers’attitudes, knowledge, and teaching skills but also the behavior of children with ADHD in class. Therefore, the programis recommended as a means of facilitating teaching and managing children with ADHD in class.