Background: The common psychiatric disorder of attention deficit hyperactivity disorder (ADHD) and the knowledge of teachers about it are well discussed in literature. While teachers can play an important role for the management of ADHD, it is not clear whether informing of teachers about children with ADHD affects their behavior and attitude toward the children. In the present study, we studied whether the disclosure of children with ADHD is associated with social rejection and negative attitude of their teachers. In addition, we studied the perception of teachers for treatment and its benefits. Methods: A total of 558 primary school teachers of students in grade I in Shiraz, south of Iran, participated in this study. They completed the questionnaires after studying one of the randomly selected four vignettes. One of the vignettes with inattentive type and one of the vignettes with hyperactive-impulsive type symptoms were not labeled as ADHD children. Results: The teachers did not show any difference in their attitude on various types of disclosed and undisclosed ADHD vignettes. The four groups of teachers were not different regarding their belief for treatment and its benefits. Conclusion: Parents of the children with ADHD could be assured that informing of teachers about the disorder does not cause the social rejection or negative attitude towards the affected children. Lack of difference among the teacher groups for the necessity of the treatment and its benefits shows that their knowledge about ADHD is not enough. Improving the knowledge of teachers about ADHD is a preceding step for disclosing the children's disorder.