Speech therapy and medical clinics receive a large number of referrals from teachers of children and adolescents suspected of having attention deficit hyperactivity disorder (ADHD) and auditory processing disorder (APD). These students manifest symptoms and behaviors in the classroom, which interfere with academic performance and the performance of daily activities, and which, according to the teachers, are "characteristic of ADHD or APD." PURPOSE: To investigate the behavioral signs and symptoms that teachers use to classify these referrals. METHOD: A questionnaire about 20 symptoms of ADHD and APD, according to Keller (1998), Chermak et al. (1998), and Reis (2005) was completed by 19 public school teachers from the city of São Paulo. The questionnaire asked the participants to classify different symptoms as present in ADHD or APD. RESULTS: The results showed that symptoms such as distraction (68.4%); conduct problems (57.8%); socially inappropriate, disorganized, and aggressive behavior (42.1%); restlessness and lack of cooperation (36.8%); hyperactivity (15.7%); hasty or impulsive behavior (10.5%); and difficulty in discriminating speech (5.2%), which occur at different rates in the 2 disorders, were frequently misclassified. CONCLUSION: Teachers demonstrated difficulty in differentiating between specific characteristics of ADHD and APD, which explains the misclassification of children with these disorders in the referrals. It appears that teachers need to have a better understanding of these 2 disorders in order to make appropriate referrals.