There are students with attention-deficit/hyperactivity disorder (ADHD) in private schools that do not receive the same assistance as students with ADHD attending public ones. Thus, students with ADHD attending private schools struggle academically. The purpose of this qualitative case study was to explore private school teachers' perception of in-service trainings for students with ADHD and how these teachers use what they have learned from these trainings, if at all, to aid students with ADHD. The theoretical framework used was Self-determination Theory (SDT). The sample was 11 teachers with two or more years of instructional experience from two private schools in San Diego County, California. Research questions on teacher perception of in-service trainings for students with ADHD and how teachers enact what they learned during in-service trainings with students with ADHD guided the study. Eleven individual interviews, one focus group, and 10 artifacts were used in the data analysis, consisting of thematic analysis using Saldana and Yin's coding processes. Five themes emerged: (1) Teachers had positive perceptions of in-service trainings for students with ADHD, (2) Teachers had negative perceptions of in-service trainings for students with ADHD, (3) Teachers do implement the strategies/techniques from in-service trainings, (4) Teachers do not implement the strategies/techniques from in-service trainings, and (5) Teachers use a variety of strategies/techniques from in-service trainings. Conclusion: Most participants viewed in-service trainings positively and used in-service strategies/techniques in classrooms. Participants believed more in-service trainings on ADHD were necessary. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]