Teachers play a crucial role in the diagnostic process of Attention-Deficit/Hyperactivity Disorder (ADHD) in students: They are often the first to identify ADHD-related behaviors in children and to signal them to parents. Research has demonstrated that the recognition and labeling of certain behaviors as evidential for ADHD by teachers vary with respect to student characteristics. This study examines if and how the association between teacher perception of students' ADHD-related behaviors and teacher suspicion of ADHD in students is moderated by teacher perception of students' cognitive capacities. Multilevel analysis was carried out on data collected in 2017 and 2018 from 939 students and 108 teachers in 15 Flemish (Belgium) and 16 Québec (Canada) schools in the context of a collaborative research project on ADHD-prevalence and identification. Results show that, when teachers perceive ADHD-related behaviors in students, they more readily suspect ADHD when students are cognitively stronger. This study suggests that teachers are more inclined to free cognitively stronger students from the blame of ADHD-related behaviors by administering them an ADHD-label.