The present study examined general and special education teachers' self-reported level of in-service training in attention-deficit hyperactivity disorder (ADHD), a common childhood mental health disorder, and the relationship between teachers' level of training in ADHD and their reported use of a range of recommended instructional and behavior management approaches for students exhibiting behavior problems. The analyses revealed that the majority of general education teachers (76%), and almost half (41%) of the special education teachers, reported having no or brief in-service training in ADHD. General education teachers with moderate to extensive in-service training in ADHD reported significantly greater use of the recommended approaches (as indicated by their scores on the Instructional and Behavior Management Survey) than general educators with little or no training in ADHD. Implications for research and practice are discussed.